nvidia 5090 connector/power-cable melting. geschmolzen ! - Page 1
Forum section: electronics / general

author: Simmed
author_rank: Frequent Contributor
timestamp: February 12, 2025, 04:53:23 pm
content: you all know the problem back when it was 4090now its 5090i learn a new word : geschmolzen

author: tszaboo
author_rank: Super Contributor
timestamp: February 12, 2025, 05:24:05 pm
content: Original 8 pin VGA power cable had like 50% margin, this one has 10% margin.But I've never seen so much crying over going from Molex mini-fit to Micro-fit. The connector is perfectly good other than the biggest cards, that are 1% of the sales (checked steam stats)

author: coppice
author_rank: Super Contributor
timestamp: February 12, 2025, 05:39:41 pm
content: That connector looks like the kind of botch up you end up with after multiple repairs, not something fresh from the factory. To need little sleeves on a new lead means either the wire or the connector are not fit for the job.

author: iMo
author_rank: Super Contributor
timestamp: February 12, 2025, 06:05:17 pm
content: More details on why it gets geschmolzen..

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 13, 2025, 03:43:17 am
content: I've seen that with power connectors in vehicles, seeing it on GPUs is pretty funny.

author: racemaniac
author_rank: Contributor
timestamp: February 13, 2025, 08:57:13 am
content: Quote from: tszaboo on February 12, 2025, 05:24:05 pmIt's indeed only for the highest end cards, but it's still quite the scandal if they engineered them so badly they will fail. Which other skeletons are there still in the closet if they do stupid stuff like this.And the video of der bauer is really good, is also an interesting discussion: can you just put 2x6 pins in parallel and hope the power will nicely split across the pins? with a connector on both sides of the cable there's a lot of room for differences in resistance between the cables, and der bauers testing showing one cable getting nearly half the current in that setup is pretty disastrous....

author: iMo
author_rank: Super Contributor
timestamp: February 13, 2025, 09:18:19 am
content: ..should have been solved 2y back..https://www.tomshardware.com/news/16-pin-power-connector-gets-a-much-needed-revision-meet-the-new-12v-2x6-connector?utm_source=chatgpt.com#xenforo-comments-3812564

author: BrianHG
author_rank: Super Contributor
timestamp: February 13, 2025, 09:41:47 am
content: This is so pathetic.If you want to deliver above 500 watts, place some god damn 2 or 4 gauge lugs on the PSP and Graphics card and let the user wire it with soft flexible 2 to 4 gauge wire the exact same way those of us do with high powered car audio amps. No more unbalanced parallel tiny baby power cables on connectors better suited for low power control signals with a 1 amp limit each. No more iffy connections when you have a dead-bolt lug crimping a cable capable of handling over 100 amp continuous without even getting warm.

author: tszaboo
author_rank: Super Contributor
timestamp: February 13, 2025, 10:30:07 am
content: Quote from: racemaniac on February 13, 2025, 08:57:13 amIt's a third party cable, that specializes in colors and fluff.I've seen badly crimped cables. It's surprisingly difficult task to hand crimp cables, and testing them is also quite difficult. As you would need to inspect every single crimp under a microscope, and electrically test to release it to a customer. At these small margins. Machines do this better, but for a boutique manufacturer...

author: racemaniac
author_rank: Contributor
timestamp: February 13, 2025, 03:08:48 pm
content: Quote from: tszaboo on February 13, 2025, 10:30:07 amThe guy who had his cable melt was indeed third party, but afaik der bauers cable wasn't, he used the cable that came with a power supply from a reputable manufacturer.

author: madires
author_rank: Super Contributor
timestamp: February 13, 2025, 04:42:34 pm
content: Someone missed electronics 101. If you need more amps take a thicker wire with a suitable connector. Simply paralleling multiple wires and contacts asks for trouble.

author: Fryguy
author_rank: Regular Contributor
timestamp: February 13, 2025, 05:02:07 pm
content: Please tell that to every consumerlevel computer psu manufacturer from the last 5+ decades , madiresYou are absolutely right , but they've been doing it forever ! The picture is a 386 mainboard power connector - and that was 1981 !Notice the 4x black GND and the 4x red +5V cables .

author: iMo
author_rank: Super Contributor
timestamp: February 13, 2025, 05:34:53 pm
content: You may also increase the voltage from 12V to, say, 48V (as the future standard for the upcoming 5kW GPUs)..And the current per pin will go down 4x..

author: benseno
author_rank: Regular Contributor
timestamp: February 13, 2025, 05:57:36 pm
content: Quote from: iMo on February 13, 2025, 05:34:53 pmand sale it as part of the water heating boiler for sustainable green future.

author: iMo
author_rank: Super Contributor
timestamp: February 13, 2025, 06:02:38 pm
content: Quote from: benseno on February 13, 2025, 05:57:36 pmThe energy will be easily to get thanks Mr. Maxwell Chikumbutso, afaik already hired by nvidia..

author: Fryguy
author_rank: Regular Contributor
timestamp: February 13, 2025, 06:29:41 pm
content: Maybe they should change their business model from "gaming hardware you can heat your home with" to "heating systems you can play with"

author: Simmed
author_rank: Frequent Contributor
timestamp: February 13, 2025, 08:18:01 pm
content: there is this paper about the frettingthe pin used inside the paper appear to be about 0.6mmthe molex 219116 is 0.64mmfor the research : presumably after 2000hrs, half the pins failon digikey219116 is us$1.1 (9.2A)212528 is around us$8 (12A, gold flashed)212520 is us$2 (20A)

author: coppercone2
author_rank: Super Contributor
timestamp: February 14, 2025, 07:23:12 am
content: does anyone think that this might just be bad/cheap plating? I.e. crap gold flash ?backfire on the 10 nanometer gold plating ? Combine with not using a crimp micrometer. Because the expensive tools are a ripoff and you don't need a ratchet etcand how about the wire, did anyone check if the gauge was right and if it was oxygen free copper? Was the crimp inspected for a proper broom? or maybe a crimp machine left a tare of insulation that got under the fold.I think there could very easily be a bad process (machine cranking out cables at warp 10 with worn dies and 0 qc)I feel like there is alot of blame going around with alot of drama with alot of assumptions being made assuming quality... there is a good reason people are generally told to solder instead of crimp if they don't know what their doing or don't have the right tools.We can't even be sure that someone is not using oxidized crusty wire too. Or that the assembly got corroded in storagemy sensationalism alarm went off because this card is generally being attacked because its expensive and unavailable and has questionable performance and nvideas sales model is questionable, none the less, its not right to just blame a rather well trusted interconnect from another company without evidence.How many scandals have we seen with poorly made cables that fail inside of desktop computers??? its not exactly rare. The cable manufacturing videos I come across on video websites (shorts) often keep me up at night. The lack of maintenance/standards in factories (even good ones) can have scary effects on the end product.The amphenol brand crimp is rated for 12 amps. It uses 16 pins, meaning 12 power pins, meaning if its working properly, you should have 12*6 = 72 amps. The card uses maybe 50 amps peak. That is still 30%. It should not go into meltdown unless you lose.. 3 crimps (138% overload)?So the 5080 is fine, the 5090 really makes a assumption your interconnects are good. I think it needs a 20 pin connector to account for crap cablesI support the idea that it should have lugs on it thoughHow much redundancy should you have? right now it looks like its running at overload if you lose 50% of your crimps (three out of six), if you lose 2 crimps your running at the limit.

author: JimboJack
author_rank: Regular Contributor
timestamp: February 14, 2025, 09:24:42 am
content: Previous Gen GPU's in servers H100/H200 in server PCIe dual slots uses the following, even the servers that cost $$$$$$ have dodgy plugs.max 600Watt -> 8PIN EPS (H200NVL) plug is rated upto 335W525Watts on that plug + 75Watts on PCIemax 400Watt-> 12VHPWR (H100NVL) they limited it to 325Watts + 75 Watts on PCIehigher power modules SXM'smax 700Watt -> SXM module (H200SXM)max 1000watt -> SXM module (B200)i thought make a hybrid plug , 4-8AWG cable into a the 12VHPWR that has a single backplane of copper , but after the video it is the GPU power design the problem, The nvidia 5090 FE module is close to the SXM module. they just copied and pasted it into a consumer product, and removed all the 'consumer power safety features to be 'green / save cost', the contact area of the pins is two small, slight resistance and you got a warm glow.only way to be certain is to Nuc it from space............ redesign.....

author: madires
author_rank: Super Contributor
timestamp: February 14, 2025, 11:49:47 am
content: Some details fromhttps://en.wikipedia.org/wiki/16-pin_12VHPWR_connector:- safety factor of 1.1 (someone mentioned that already)- connector lifespan is 30–40 mating cyclesThe obvious issue is the safety factor. Just one poor contact or crimp can exceed that. And don't forget about the buck converters on the card. If they get less voltage (because of the voltage drop across the bad wire/contact) they'll take more current. The story is similar to paralleling diodes.

author: Ranayna
author_rank: Super Contributor
timestamp: February 14, 2025, 01:08:02 pm
content: I asked this in the other thread in the computing section, but i think the Dodgy technology section is frequented more oftenWould voltage regulators that regulate down from 24 or maybe even 48 volts be significantly larger or less efficient than regulators that regulate down from 12 volts?I think unless the energy consumption will be reduced (which i would like but don't expect), the only safe way i see is to up the voltage. Just like USB-PD did.And if you can isolate the added supply from the supply from the PCIe Slot, you wouldn't break mainboard compatibility, you would just need a new power supply.

author: Marco
author_rank: Super Contributor
timestamp: February 14, 2025, 01:12:41 pm
content: Don't those things get connected to the PSU with 3 8 pin MOLEX each almost as large as that one connector?

author: coppice
author_rank: Super Contributor
timestamp: February 14, 2025, 01:25:07 pm
content: Quote from: Simmed on February 13, 2025, 08:18:01 pmIts amazing how rapidly many flat contact pins wear away in the presence of quite modest levels of vibration, such as you might get from fast running fans. We used to have numerous problems with socketed ICs in airborne development systems, where the legs of socketed ICs (ones, like EPROMs, that needed to be quickly exchangeable) could completely wear away in as little as 200 airborne hours. Luckily, just as we were seriously hitting this problem, turned pin sockets appeared in the market, andwe switched to those. Our problems went away. There is a reason airborne rated connectors aren't built like those Molex ones.If they are using connectors which are not massively overrated, to maintain their rating after some contact degradation, they are asking for trouble in a fan cooled product.

author: tooki
author_rank: Super Contributor
timestamp: February 14, 2025, 01:52:28 pm
content: Quote from: tszaboo on February 13, 2025, 10:30:07 amIt is not difficult at all to hand-crimp when using the correct tools. (In fact, I own an original Molex crimper for Micro-Fit contacts, and every crimp has come out flawless.)But the chances that any manufacturer is using hand tools to crimp is practically zero. Individual DIYers might, but power supply manufacturers will likely farm out production to a cable assembler, who will use semi- or fully-automatic crimping machines. Those assemblers also should have the tools needed to test their crimps correctly. Even a boutique company is probably going to outsource the cables to an assembler.Quote from: coppice on February 12, 2025, 05:39:41 pmFrom the look of it, those are splices on the four sense pins, which are smaller, and they wanted to use the same gauge wire for all the lines in the harness.

author: coppercone2
author_rank: Super Contributor
timestamp: February 14, 2025, 02:25:07 pm
content: it might a question of deceptive advertising too, because the front page for the connector housing says 12/a per pin, the datasheet says 9.5 amp per pin. Clever way to hide the derating that is expected for the intended useEt tu, amphen?

author: iMo
author_rank: Super Contributor
timestamp: February 14, 2025, 02:34:47 pm
content: The connector and cables are definitely not good enough for safely handling 600-800W (the max with 5090 I saw).25A per single wire in below measurement..Either it gets much beefier gold plated connectors, or, they start to use those 48V I mentioned above (4x lower current).

author: coppercone2
author_rank: Super Contributor
timestamp: February 14, 2025, 02:36:38 pm
content: you know raising voltage does have its on problem, that is welding machine territory.More pins is always an option50+ volts malfunctioning gets interestinghigher voltages defeat insulation better I think, instead of melting it starts blasting its way through things

author: iMo
author_rank: Super Contributor
timestamp: February 14, 2025, 02:41:06 pm
content: Raising the voltage to 48V is not a big problem today "from technical point of view" as there are modern step down designs and parts available..Perhaps the high voltage "safety" could be a question with 48V as usually 12V is considered safe even when messing in the computer case fully flooded with the cooling water..Quote from: coppercone2 on February 14, 2025, 02:36:38 pmThe current creates the welding effect, not the higher voltage.48V is not much, the wires isolation and the connector may stay the same as it is today, imho..

author: coppice
author_rank: Super Contributor
timestamp: February 14, 2025, 02:50:33 pm
content: Quote from: iMo on February 14, 2025, 02:41:06 pmWhen you look at the 12V 200A supplies for the server market, where almost all of that 12V is immediately converted to a lower voltage for use, the first thought is why 12V? It makes the plumbing is so thick, and inflexible. Why not 24V or 48V? 48V keeps things below any regulatory threshold for a dangerous voltage. The industry has taken a while to get get both the server and consumer markets to focus around supplies with a simple single voltage output, but it feels like they focussed on the wrong voltage.

author: tooki
author_rank: Super Contributor
timestamp: February 14, 2025, 02:56:24 pm
content: Quote from: coppercone2 on February 14, 2025, 02:25:07 pmWhere do you see that 12A claim? Because what I see says 9.5A on the page, just like the datasheet:https://www.amphenol-cs.com/product/10161719124glf.htmlInterestingly, Molex specifies 9.2A for their equivalent products.

author: tooki
author_rank: Super Contributor
timestamp: February 14, 2025, 03:03:20 pm
content: Quote from: coppercone2 on February 14, 2025, 02:36:38 pmSo what? Spot welders operate at very low voltages, typically just a few volts. That doesn’t mean that 5V-12V power (voltages within what’s used for spot welding) is difficult to work with.USB PD uses higher voltages, including 48V to achieve 240W.You know what else is 48V? Analog phone lines. And they certainly weren’t creating hazards.

author: iMo
author_rank: Super Contributor
timestamp: February 14, 2025, 03:04:35 pm
content: Handling 48V and say 5A per wire is way much easier, indeed.What blocked that higher voltage use in the servers was the step-down converters technology, imho.Amateur radio operators know that well too, for example, as the 12-13.8V and 15-20A is the standard their 100W transceivers consume. Would be better if we could operate from around 50V and have much less current (ie. when battery operated, lower currents are much better).

author: coppice
author_rank: Super Contributor
timestamp: February 14, 2025, 03:07:41 pm
content: Quote from: tooki on February 14, 2025, 03:03:20 pmActually analogue phone lines did carry hazardous voltages, and the RJ11 was chosen to be small enough to pass the finger test without a shutter. -48V DC + the peak negative swing of the ring signal can exceed the peak of 230V AC mains.

author: tooki
author_rank: Super Contributor
timestamp: February 14, 2025, 03:12:35 pm
content: Quote from: iMo on February 14, 2025, 02:41:06 pmIndeed, the connectors the 12VHPWR connector is based on (the 3mm pitch Amphenol Minitek, Molex Micro-Fit, and TE Micro Mate-n-lok) are rated for aminimumof 250V AC or DC, with the Molex and Amphenol ones rated for 600V. There is no doubt the 12VHPWR connector itself is capable of way more than 12V, but that it’s specified that way so that nobody gets the bright idea to make a proprietary higher-voltage system using that connector. Given that that connector system allows for a huge number of keying combinations, it’d make sense to key a 24V or 48V version differently, even if it’s otherwise the same.

author: tooki
author_rank: Super Contributor
timestamp: February 14, 2025, 03:18:10 pm
content: Quote from: iMo on February 14, 2025, 03:04:35 pmThat is not a difficult problem, and is one that was solved ages ago. Every switch-mode power supply begins by rectifying the incoming AC to DC (so a rectified voltage of anywhere from 127 to 354V DC for the typical 90-250V input range).Not to mention that tons of telecom equipment operates on 48V DC (-48V, to be specific) already, so the technology to DC-DC convert that to the typical logic voltages is a thoroughly solved problem.

author: wraper
author_rank: Unknown
timestamp: February 14, 2025, 03:22:32 pm
content: Quote from: iMo on February 14, 2025, 02:34:47 pmHe cut 4 out 6 12V wires to demonstrate that GPU does not detect uneven current sharing if some pin makes worse connection than the rest. Therefore current per pin can easily go over the max allowed considering there is barely any current per pin margin left even when there is a perfect contact on all pins (rated 9.5A per pin).

author: tooki
author_rank: Super Contributor
timestamp: February 14, 2025, 03:28:58 pm
content: Quote from: coppice on February 14, 2025, 03:07:41 pmFirst off your numbers are wrong; the ring voltage is 90V, so its Vpk is 127V. Add 48V to that and you get 175V, nowhere near the Vpk of 230V mains, which is 325V.But secondly, the “proof” is that electricians must use VDE insulated tools for working on energized 230V mains circuits (and even then it’s allowed only when absolutely unavoidable), while telecom technicians can work on energized phone lines without any special precautions. Similarly, the requirements for the wiring are very different.

author: iMo
author_rank: Super Contributor
timestamp: February 14, 2025, 03:41:53 pm
content: Anyhow, for say an 2kW 6090 GPU card I would go with the 48V and with the same connector and wires as it is today. With 6 wires you will get 7-8A per wire..

author: coppice
author_rank: Super Contributor
timestamp: February 14, 2025, 03:57:46 pm
content: Quote from: tooki on February 14, 2025, 03:28:58 pmThe maximum ring voltage specified for digital exchanges was typically 105V AC, but if you were designing equipment it had to tolerate more like 150V AC, as that is what you got from many old Strowger exchanges. 150*1.4 + 48 = 258V peak. I misremembered just how high it got, but its a seriously high voltage, and telecoms people are wary of touching circuits which might suddenly ring. Its current limited, and isn't that likely to kill an adult directly, but if you are up a ladder working on a line, and it rings you'll likely jolt enough to fall off that ladder. Its certainly enough to kill a small child. One of the gotchas you'll find with the reliability of telecoms circuits is designers ignoring just how much energy is in one of those cycles. Many things, especially in the age of small SMD parts, that have an RC quench circuit across a phone line relay eventually blow the resistor or capacitor apart, because the designer didn't allow for the relay closing at peak stored energy. I've designed things that would only close the relay at a null in the ring cycle, which I was detecting anyway, because that's what ring detectors do.

author: BrianHG
author_rank: Super Contributor
timestamp: February 14, 2025, 06:38:48 pm
content: Again, with loads passing 50amps total, 100 amps overclocked, why haven't they switched to 4awg to 2awg cables with lugs like you see in the attached picture?These cables will not get hot and will have the overhead room for 100amp loads soon to come. 1 contact, no iffy connections...Pro car audio have been using these connectors for their audio years without fail so long as the cables you used were correctly sized and crimped, and they go well beyond 200 amps.

author: Simmed
author_rank: Frequent Contributor
timestamp: February 14, 2025, 07:33:50 pm
content: there is a paper on the interesting effect of contact gouging and oxidationhttps://ieeexplore.ieee.org/document/4318220in the chart, it shows the fretting in 3 phasesi guess this is totally random in the case of 219116each contact being loosely held will definitely scrape the pin at all kinds of angles and different pressure219116 molex tin is only 1.5um thickand so according to the chart resultthe contact resistance could have a range of maybe +/- almost 1 magnitude?if we consider the PSU cable to be around 30cm, this is about 5mR resistancethen there is 2 contacts, 1 at the GPU, 1 at the PSU. which could add annother 10mRassuming a single 219116 pin could swing its contact from 2mR to 15mRwe would see the following on LTspice that the current can swing from 5A to 10Athen from this websitehttps://www.hardwareluxx.de/index.php/news/hardware/grafikkarten/65482-12v-2%C3%976-12vhpwr-wieder-berichte-%C3%BCber-schmelzende-stecker.htmlthey did some tests which is also quite similar in resultbut the low current pin on his test drops to 3Awhch means on a pin with just the right amount of oxidation, the pin contact could be around 0.05 ohmand these are suppose to be brand newso if we use similar data and say a number of contacts have gone thru a some iterations of frettingand all the contacts rises in resistance and 1 pin scrapes the copper and hits a lowie : 5 pin @ 0.03, 1 pin variablethe 1 pin hitting copper low resistance may have a good chance of passing very high currentin the simulation it shows 17Ain the case of der8auer, he hit 20Ait is all a matter of chance and right combinationin this forum there are many threads about fretting prevention using contact grease (and deoxit)i wonder if any of the reviewers are ever going to try it ?taking it furtherso even if for a 4 pin scenario, LTspice shows a single pin could still hit 15A6 pin, 4 pins have the correct criteria and 1 or 2 pin could go into meltdownfor a 6 choose 4 scenario, this is a 1 in 120 event chancemaybe molex should make the connector HIGH SMOKE, UL-94(high smoke special plastic)a SMOKE puffing connector will give a very nice indication of improper seatingsee ? there ! that 1, it is smoking !i think this is the best idea, a self smoking connector that starts emitting smoke at say about 70Cat 70C, the user may still have a minute to press the power button ?

author: coppice
author_rank: Super Contributor
timestamp: February 14, 2025, 07:46:10 pm
content: Quote from: BrianHG on February 14, 2025, 06:38:48 pmHow do you expect this 2AWG/34mm^2 cable to be formed into the tight curves needed in the limited space within a PC? Its about as flexible as a zealot. There is a reason many systems with high DC currents to transfer use a cluster of separately insulated wires. What is less clear is why many don't pay more attention to the connector quality, and to being able to verify the entire cluster is properly connected.

author: beton_kruglosu_totchno
author_rank: Contributor
timestamp: February 14, 2025, 08:54:41 pm
content: The fundamental problem is that receptacle resistance can vary by a factor of several times. It's only a problem if cable resistance is low.If cable resistance was several times the maximum receptacle resistance the current would be balanced almost perfectly in any condition regardless of wear and plug position.Even adding 1 resistor to each wire is enough to fix the issue permanently.

author: Simmed
author_rank: Frequent Contributor
timestamp: February 14, 2025, 09:18:10 pm
content: Quote from: beton_kruglosu_totchno on February 14, 2025, 08:54:41 pmin other thread, i tried your suggestion. say add 0.03R, this at 8A will dissipate 2win simulation, a gouge lane 0.03 + 5x normal 0.06, the gouged lane will pass 14A. the single limiting R 0.03 @ 14A = 5.9wwe could try higher 0.05, but the burden power loss @ 8A is now 3w (x6 lane >18w)

author: BrianHG
author_rank: Super Contributor
timestamp: February 14, 2025, 09:21:00 pm
content: Quote from: coppice on February 14, 2025, 07:46:10 pmFair enough. Though, the 4awg cables used in car audio are super flexible and are designed for tight turns.Even 6awg will do, and those would fit 2 adjacent PCB mounted lugs in a dual slot PCI card.

author: coppercone2
author_rank: Super Contributor
timestamp: February 14, 2025, 09:23:43 pm
content: the arc does not sustain at low voltages, you need to get it to 50-60 volts before it becomes useful as a tool or particularly destructive, at around 10 amps.Low voltage arcs dont draw very well

author: Simmed
author_rank: Frequent Contributor
timestamp: February 14, 2025, 09:24:11 pm
content: Quote from: BrianHG on February 14, 2025, 09:21:00 pmlets go

author: coppice
author_rank: Super Contributor
timestamp: February 14, 2025, 09:24:41 pm
content: Quote from: beton_kruglosu_totchno on February 14, 2025, 08:54:41 pmI've seen connection systems where several separate wires, for flexibility in the cable, terminate in a single large lump of metal. That way you only have a single connexion, so connection resistance imbalance is eliminated, but you have the flexibility which is needed. Off hand, I can't remember where I have seen that approach used, but I definitely have.

author: beton_kruglosu_totchno
author_rank: Contributor
timestamp: February 14, 2025, 09:27:52 pm
content: Quote from: coppice on February 14, 2025, 09:24:41 pmSure but what I suggest is a braindead straightforward solution if you want to keep both an 5090 and your house.Also, merging the wires at the connector won't fix the pin imbalance. It's just that PSU won't burn like it did in Derbauer's video.Quote from: Simmed on February 14, 2025, 09:18:10 pm0.03 Ohm is too small, just do 0.2.That's 10 W of heat.(I miscalculated it) Would be nice if if was distributed for whole cable but even an adapter could be made to dissipate that (or what's better cut the cable and solder the resistors to 12V).

author: BrianHG
author_rank: Super Contributor
timestamp: February 14, 2025, 09:30:34 pm
content: Quote from: coppice on February 14, 2025, 09:24:41 pmThat approach is typically use in class AB audio amps where paralleled output transistors all have small series resistors to ensure slight DC offsets from imperfect transistor matching/DC offset doesn't make 1 transistor bear all the heat/grunt of the output drive.

author: thm_w
author_rank: Super Contributor
timestamp: February 14, 2025, 10:31:56 pm
content: Quote from: madires on February 14, 2025, 11:49:47 amSays 20mR max after 50 cycles: 10132447-121PLFhttps://www.amphenol-cs.com/product/10132447121plf.htmlhttps://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-1291.pdfIf it was in spec its not an issue, assuming you don't unplug and replug your GPU every week, but poor crimp or dirty contact would put it outside of that as you say.I don't know the mini-fit jr exact number (pcie 8 pin), its 40-75 cycles, so similar. But I guess it doesn't matter when you over-spec the rating, it can easily last much longerQuote from: BrianHG on February 14, 2025, 09:30:34 pmYes but transistor resistance decreases with heat. That is not the case with copper or brass, resistance goes up with temperature.

author: rsjsouza
author_rank: Super Contributor
timestamp: February 15, 2025, 01:07:40 am
content: After I saw a video of people paying enormous amounts of money to scalpers, I think this is a great business opportunity to sell "compuphool-grade"TMpower cables, with oxygen-free 99.999999% Cu purity, crystal beads to help align the electron spins and guarantee the best clarity on your video signal.

author: coppercone2
author_rank: Super Contributor
timestamp: February 15, 2025, 01:14:45 am
content: how about electrical material grade, made with real electrical materials

author: tszaboo
author_rank: Super Contributor
timestamp: February 15, 2025, 02:57:45 pm
content: Quote from: BrianHG on February 14, 2025, 06:38:48 pmTorque control. People would undertorque it leading to fires or restarts. Or overtorque it leading to RMAs.Quote from: coppice on February 14, 2025, 02:50:33 pmAs I understand, there is some process jumps going from 16V rated semiconductors to higher rated semiconductors. Same at 5.5V or 30V or so. Mosfet losses go up or something like that. In any case, with 48V input the SMD capacitors also drop their rating, ripple current goes up. There aren't many multiphase converters for those voltages. These GPUs use like 16 phases.What you say makes sense on some level, but I think currently backwards compatibility is more important (for them). And someone calculated that copper is less expensive than semiconductors.

author: tszaboo
author_rank: Super Contributor
timestamp: February 15, 2025, 03:09:03 pm
content: Anyway, If I would need to select a connector, it would be a variation like this:XT90 with sense lines, and digital communication. Maybe some variant with XT60 pins, and 4 high current connection.Actually, thinking another minute about it, they could use the extension of the USB PD protocol to set the voltage and current.

author: Simmed
author_rank: Frequent Contributor
timestamp: February 15, 2025, 06:14:35 pm
content: looks like google has some of these 48v rail thingy alreadyhttps://semianalysis.com/2023/08/01/energizing-ai-power-delivery-competition/H100 SXM version on 48v (pic : H100 backside)H100 pcie appears to be 350w llimitedthen someone in china created a pcie converterhttps://wccftech.com/sxm-to-pcie-adapter-board-convert-nvidia-h100-ai-gpus-1-2-slot-graphics-cards/so 700w on 2x 8pin (8 lanes +/-) = about 7.3A per laneon digikey molex series 43045same 0.64mm pin ( UL rating 8A, IEC rating 5A)but on 219116, the same pin is 9.2A ratedbonus linka research group found the nvidia-smi (sys management interrupt ?)have whatlooks like poor reporting of its own power activityhttps://arxiv.org/html/2312.02741v2on 4090 it seems like it under reports the power by a whooping 12%i wonder what 5090 numbers look like

author: coppice
author_rank: Super Contributor
timestamp: February 15, 2025, 06:23:19 pm
content: Quote from: Simmed on February 15, 2025, 06:14:35 pmA few years ago it seemed like the entire data centre industry would move to servers running from 48V DC, just like most of the telecoms industry. As with telecoms, the mains would charge battery sets, and the battery sets would run the servers.

author: madires
author_rank: Super Contributor
timestamp: February 15, 2025, 07:20:19 pm
content: Wiring, breakers, PDUs and so on for 48V DC are expensive compared to standard AC stuff. And the connectors used are usually spade and ring lugs. Power-wise PSUs can be anything up to a few kW each.

author: AVGresponding
author_rank: Super Contributor
timestamp: February 16, 2025, 10:55:29 am
content: The 48V batteries were due to the legacy PSTN systems, which are being phased out. As those disappear, I expect other systems to start using battery voltages more suited to their specific use case.

author: tooki
author_rank: Super Contributor
timestamp: February 16, 2025, 11:36:22 am
content: Quote from: madires on February 15, 2025, 07:20:19 pmWell sure it’s more expensive, since the currents are higher and DC is harder to disconnect under load. But it’s that much worse with 12V.

author: iMo
author_rank: Super Contributor
timestamp: February 16, 2025, 12:02:51 pm
content: What chatgpt knows about 48V:Quote

author: Ranayna
author_rank: Super Contributor
timestamp: February 16, 2025, 01:52:52 pm
content: Quote from: AVGresponding on February 16, 2025, 10:55:29 amIt still has quite widespread use in IT.Power over Ethernet is nominally 48 volts. AFAIK the newest USB-PD Standard also goes up to 48 volts to be able to deliver 240 watts.I assume this was chosen because of it's prevalence in old phone systems.48 volts is still relatively far below the SELV threshold of 60 volts.I don't think 48 volt will go away soon.

author: madires
author_rank: Super Contributor
timestamp: February 16, 2025, 02:16:35 pm
content: Quote from: iMo on February 16, 2025, 12:02:51 pmObviously not much.We powered servers for essential IP services with 48V DC already in the late 90ies, besides tons of routers, switches and so on.

author: coppice
author_rank: Super Contributor
timestamp: February 16, 2025, 02:55:17 pm
content: Quote from: madires on February 16, 2025, 02:16:35 pmThere was no choice. The core methodology of most telecoms infrastructure systems was rectify to -48V DC, charge a big battery set, and run everything from that. The server and IP equipment makers had to start offering a 48V PSU option to be able to access that market. The very complex high end super efficient 48V supplies which are commonplace today are often still referred to as simply rectifiers because of that history.The big change on the telco side was previously we had to develop things like telephone exchanges for a minimum of 15 years continuous operation, and suddenly the telcos were buying stuff they fully expected to replace in a couple of years.

author: ejeffrey
author_rank: Super Contributor
timestamp: February 16, 2025, 06:37:05 pm
content: Quote from: madires on February 13, 2025, 04:42:34 pmParalleling wires to meet current requirements is almost universal in this sort of intra chassis board to board wiring. It's often much preferable to having a single wire and connector sized for the load Done properly it works perfectly fine.Done properly means derating the per pin current to account for imperfect current sharing. Doing it properly means accounting for variations in crimp quality and making sure it can be reliably mated in the field. Running 6 parallel wires at 90% the rated current with no active balancing and no voltage drop monitoring is not OK. Precious standards used fewer parallel wires with significantly larger safety margins

author: coppercone2
author_rank: Super Contributor
timestamp: February 16, 2025, 06:48:35 pm
content: if you use the front page number of 12.5 suddenly it does not look so bad. maybe someone verified with chat GPTyou lose 30% of theoretical to the housing

author: coppice
author_rank: Super Contributor
timestamp: February 16, 2025, 06:50:11 pm
content: Quote from: ejeffrey on February 16, 2025, 06:37:05 pmIt tends to work out well in many cases, as the individual contacts are substantially over rated for the intended load. If the currents don't balance well, no single contact is usually overloaded, unless there are some badly dirty or distorted ones. However, this new connector is running each contact near its rating. Even a modest imbalance is pushing one or more contacts well beyond its rating.

author: coppercone2
author_rank: Super Contributor
timestamp: February 16, 2025, 07:42:16 pm
content: Well Unless there is a weight problem there is no need to run things so close to limit. its not a space rocketif you want a videophool card, how about making a set of cables and crimps from pure silver or a specially developed lower conductivity high silver alloy to bring that margin from 10 to 20 percent instead of changing a cable? Perhaps the contacts might be a bit less lossy and the wire would conduct more. its a reasonable alternative to a 18 or 20 pin connector

author: coppice
author_rank: Super Contributor
timestamp: February 16, 2025, 07:48:14 pm
content: Quote from: coppercone2 on February 16, 2025, 07:42:16 pmI think nVidia are concerned about space, rather than weight. They have tried to minimise the space taken for a flexible connection, but put tolerance at the bottom of their list of factors to consider. Not a good trade off. I think the really damning thing is the 4000 series had these problems, as they learned nothing.

author: Simmed
author_rank: Frequent Contributor
timestamp: February 16, 2025, 08:39:29 pm
content: Quote from: coppice on February 16, 2025, 06:50:11 pmyou can see the older molex 43045 (year 2017) with same 0.64mm pinthe older pdf has a derating chartit goes to 5.5A (18AWG W-B #12circuit) specified for 30Cwhich is adequate for >700wso someone back then already created a working reference chartbut AWG16 was not included for some reason

author: coppercone2
author_rank: Super Contributor
timestamp: February 22, 2025, 06:52:22 am
content: Does anyone think that the lack of availability of the cards is kind of like investor / ad fraud? I was thinking that its like a way to try to ride out the wave of being a company that is also for gaming but not have any products available for gamers? Not to say they dont make a product but they seemed to have created a expectation that its also for gaming (not just AI work i.e. corporate sales) but then really not deliver substantial things in that segment... its kind of a thing you do in privateI had something similar in a class action for a law suit for a stock holding, something about misrepresenting the company with public statements to create stock value on BS claims to claim the company is going to be involved in things its not involved in (this was for power infrastructure development (energy transport, etc)it seems to be on some kind of fine line .did they sell like 5 of these cards in the last month lol? they don't really to be in that segment they say their in. I keep hearing about scalpers but if there was that many scalpers they would drive their own prices down to reasonable numbers (reasonably overpriced, rather then absolutely preposterous). (I feel like only a total noob seller would sit on something expensive to wait till it gets more expensive when its a tech thing, you usually get burned pretty fucking quickly doing that when you see your gadget went from $700 to $30 in 6 months cuz something new came out lol, when it comes to currently-in-demand industrial/corporate electronics, like network gear, you obviously want to move that as fast as possible at maximum profit, especially when you know more is on the way)It means there is no competition, aka scalpers have tiny inventory. A cartel could do it, but the claim is that isolated individuals are causing all this. It makes me think they aint acutally make more then a handful of cards, just to retain advertising on recreational crap.And if its truely meant for super limited production, you would imagine the PCB is not going to be scrutinized, so the shitty connector makes it in. No one is going to do proof reading unless its alot

author: beton_kruglosu_totchno
author_rank: Contributor
timestamp: February 22, 2025, 07:54:10 pm
content: Quote from: coppercone2 on February 22, 2025, 06:52:22 amIMO Nvidia is nowhere close to fraud.1) They never disclosed any production plans.2) Releasing their product before AMD does have economical advantage even tho is's paper launch. They got to release their new technology which can now be adopted more easily than before embargoes.3) They got the upper hand in marketing bullshit which AMD now has to struggle against.4) They absolutely have plans to ramp up production, they would not have that many partner cards if they did not plan to ramp.

author: coppice
author_rank: Super Contributor
timestamp: February 22, 2025, 08:54:34 pm
content: Quote from: coppercone2 on February 22, 2025, 06:52:22 amI suspect nVidia may been caught off guard. Reviews of the new cards aren't showing any fantastic results, so nVidia might not have expected a huge demand. Does anyone have an explanation for why people would be paying way over list price for an undramatic improvement?

author: coppercone2
author_rank: Super Contributor
timestamp: February 22, 2025, 09:05:39 pm
content: because people have really old cards and want a improvement, alot of people never bought 4000 series cards or even 3000, IMO because there was no games for it.The biggest games that are referenced as being demanding1) shadow of tomb raider (2018), good game but its single player and pretty old now, its kind of a stretch that someone would be that excited about it to buy a new card2) cyberpunk, which basically was a dumpster fire that got put out and people say its somewhat good now but I don't think people flock to it because it got a shit load of negative reviewsIf there was a sick game that came out like half life 3, say 2-3 years ago (that had the prospects of big online games, popular mods, etc) , I think ALOT of people would be on the 4000 series cards because it would be worth upgrading. If you follow game news, basically alot of recent AAA titles that could use the card are hilariously bad (i.e. starwars outlaws, worth watching just for the 'bug' videos, or those pirate games). I think the big question was "why should I upgrade from something like a 1000 series GTX card"? (and all these games play pretty good on a 1080.. there is like a few settings like FXAA that kill the card, but its a pretty small improvement, all things considered)All the great games just don't require better graphics cards (because its a small team that made something novel without resources to figure out how to use a AAA+ graphics card), and the nice looking games turned out to be corporate 'camels' that have been getting shot up by reviews for more then a few years now.But as the price of monitors falls, i.e. 4k Gaming, and possibly 8K gaming, suddenly the card has use again, for titles that don't have a team of 5000 graphics developers because you simply need more of the same thing being done.And another thing I noticed is that there is alot of GOOD remasters that have been developed, and pretty interesting graphics update mods (shaders, etc) for games that people LOVED, that have been coming out maybe 2022+, so there is some reason for people to be interested in upgrading a dinosaur.Some of these remasters are getting people back into gaming that were gone for a decade or more lol, because they don't have 'board room decisions' in the game to get rid of 'quirks' people mastered or enjoyed (i.e. no auto assist everything, non linear confusing levels that you need to learn, so forth)... once you start noticing that everything was made by a committee for the calculated 'average player' (that does not exist) ... many new games are totally uninterestingI honestly think the entire reason the 5000 series got demand is because they put graphics for half life 2 on the nvidea webpage.Seeing that is like feeling something under your feet after escaping 'the island" (in the style of logans run, thx, the island, moon, etc) where you notice everything is some kind of drugged out clone. Like old parks (camp fire, big wooden blocks, rockets, fireworks, sandbox and people getting scrapes, burns and the occasional broken arm vs the mental hospital like ASIC they turned parks into lol)

author: coppice
author_rank: Super Contributor
timestamp: February 22, 2025, 09:09:56 pm
content: Quote from: coppercone2 on February 22, 2025, 09:05:39 pmThat's an excellent reason to want one, and put in an order for when they are available. Its a very poor reason to pay over list price for one. You usually need to see a clear "shiny new thing" quality for that, not a modest upgrade after 2 years of the 4000 series.

author: Simmed
author_rank: Frequent Contributor
timestamp: February 23, 2025, 12:15:32 am
content: https://www.theverge.com/news/617901/nvidia-confirms-rare-rtx-5090-and-5070-ti-manufacturing-issuelolhow do you forget the ROP ?so in order to know this defect, you must check for it.if you are just any other gamer, very likely you wont know there is a defectand it must be a die issue since nvidia did not announce a firmware fixQuote

author: coppercone2
author_rank: Super Contributor
timestamp: February 23, 2025, 12:45:03 am
content: Quote from: coppice on February 22, 2025, 09:09:56 pmWhat I am saying that there was massive stagnation in video games for the last... long while (like 5 years)... and now they started putting out remasters and maybe there is a few games on the horizon people want, so there is an unusually large amount of people that got eager for a upgrade this quarter. That could explain some extra demand, maybe. And since they stop production of the other series, people are worried about getting some card thats been burned out doing overclock bitcoin mining or whatever.I think repeated stinky fails with the bugged out unfinished AAAA games just made a great deal of people apathetic towards upgrading their hardware. I think way more 4000 series cards would be sold if games were consistently good, and then the 5000 series would not be appealing at all... but since we got to skip half a decade, it some how ended up being useful lol.But as for paying OVER the list price, I don't know whos doing that. Most gamers are frugal. I got a little panic thinking if its some how going to be like unobtanium because of trump? could large amounts of people just be thinking its the last time you can buy a good videocard that's future proofed for like the next 4 years ?(and its not, because the VRAM is too low for high performance gaming or rendering on higher resolutions, you need the ram)I can see why people want it. but not urgently. urgent was when your pentium III can't run half life 2 a month after release when the internet was going crazy, there is nothing even close to that right now. I feel as much urgency for it as replacing a oven light, 20 years ago it felt like getting ready to get off a boat to explore the new world.

author: Simmed
author_rank: Frequent Contributor
timestamp: February 24, 2025, 05:07:59 am
content: good lord nvidia H200 system1 unit is USD380kadd to basket ?https://www.broadberry.com/xeon-scalable-processor-gen4-rackmount-servers/nvidia-dgx-h200

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2025, 05:21:17 am
content: I wonder if the resulting algorithm will suggest seasonings to use on eagle after being asked about coins

author: thm_w
author_rank: Super Contributor
timestamp: March 14, 2025, 09:34:55 pm
content: tldr:When new connectors tested, directly soldered to thick wires or PCB, it can easily take over spec. Which is not too surprising.But maybe this guy will do more tests (repeated cycling, etc.).

author: BrianHG
author_rank: Super Contributor
timestamp: March 20, 2025, 09:07:03 pm
content: Quote from: tszaboo on February 15, 2025, 03:09:03 pmLinus chose the same connector. (Or his engineers did...)

author: SteveThackery
author_rank: Super Contributor
timestamp: March 20, 2025, 09:49:11 pm
content: Quote from: coppice on February 14, 2025, 03:57:46 pmHang on, that doesn't sound right. Not for the UK, at least. 50 years ago I worked as a linesman for BT (actually "Post Office Telephones" back then), and then moved into the exchange (Matlock, in Derbyshire) for a few years. The line voltage was nominally -50V (not -48V) and the ringing voltage was 75VAC. I can't be certain, but I think all the Strowger exchanges used similar ringing machines with similar voltages. The only thing that changed was the frequency: older Strowger exchanges had a 16.7Hz ring, and later ones a 25Hz ring.No special provisions* were made for working with those voltages, and in fact the standard issue wire cutters (actually "Nippers, Diagonal, 5 inch") had uninsulated handles.In the exchange there were countless places where you could touch a non-current-limited -50V. Most of the time you can't feel it, and some of my colleagues never felt a shock. However, on hot days when my hands were sweaty, I got quite a few unpleasant shocks.*Interestingly, there was a form of physical (not electrical) protection provided. It was a leather cover for the back of your hand for use when working on the main distribution frame (MDF). The MDF bristled with metal contacts, and if you got a shock it wasn't unusual to rake the back of your hand on the adjacent contact block. The leather provided good protection.

author: Simmed
author_rank: Frequent Contributor
timestamp: March 26, 2025, 12:18:18 am
content: de8auer dismantling the Nvidia interviewNvidia is so full of bullshit2:06 The launch issue3:03 RTX & DLSS as default?3:57 Availability & “Pre-Order”6:29 MSRP & pricing issues7:03 Scalping7:37 Performance of the 50 series8:07 Chip development10:05 The problem with connectors and cables12:04 Cables from “third-party suppliers”14:34 Wear and tear on the connector?15:31 Assigning blame16:19 Material analysis17:31 Melting cables18:27 Number of samples19:06 Conclusion on the connector20:05 Summary/Conclusion20:43 OutroBS interview with BS answersNvidia cleanly push the melting connector blame on everybody else and not their design

author: madires
author_rank: Super Contributor
timestamp: March 26, 2025, 11:39:24 am
content: Another Nvidia treat: blackmailing media regarding test samplesSome media outlets therefore boycott testing Nvidia products.

author: beton_kruglosu_totchno
author_rank: Contributor
timestamp: May 04, 2025, 09:10:35 am
content: Derbauer has measured resistances post-mortem.https://youtu.be/h3ivZpr-QLs?t=994It's somewhat lengthy, he subtracts wire resistance only at 23:07Wire 3 is what melted as he says. This can't be 100% reliable of course since the plug has already melted.

author: Simmed
author_rank: Frequent Contributor
timestamp: June 03, 2025, 12:47:34 pm
content: 96Gb GDDR7 memoryonly US$10,000 a piece