Finding a suitable fan for a GPU heatsink - Page 1
Forum section: electronics / general

author: Halcyon
author_rank: Unknown
timestamp: October 23, 2024, 09:08:34 am
content: Forgive the basic question, however I'm not exactly sure what to search for. I'm after a fan to fit this video card. It's had a fan installed previously however it's missing. I don't have the proper tools to be able to crimp my own connectors, so ideally one with the right connector on it would be great (although I can cut the wires and solder on an appropriate pre-terminated lead if I need to).I took the following measurements using my callipers:Heatsink size: 37.5 mm x 37.5 mmHorizontal space between heatsink fins: 2.0 mmConnector size (shroud): 7.6 mm x 5.9 mmConnector (pin-to-pin): 3.0 mmConnector pin diameter: Approx. 0.9 to 1.0 mmThis is for a 3D accelerator card which runs quite hot, so airflow is fairly important, although I don't want it to sound like a jet engine, so a decent compromise between sound level and airflow volume is ideal. Being a 2-pin fan, there is no speed control.The other question I have is, should it be sucking air away from the heatsink/card, or blowing it back towards the card? Does it matter?I don't mind paying extra for something of decent quality, so brand recommendations would be appreciated.

author: Ranayna
author_rank: Super Contributor
timestamp: October 23, 2024, 10:18:39 am
content: I see no mounting holes for a fan. Did the card really come with fan?I have seen that a couple of times in the past, that a fan header was present, but no fan was installed.It could have been a binning process after manufacture of the cards, or a deliberate limit imposed on a subset of cards that were then sold cheaper, or maybe someone decided that a fan was not required after all. Could also have been originally an OEM card, intended for use in a specific case with external airflow.Do you know the name of the card?Is it this one?https://www.classicvga.com/product-page/diamond-monster-fusion-bansheeThat seems to match the placement of the memory modules and the Silkscreen, but it would mean someone did not only replace the fan, but the heatsink as well.

author: wraper
author_rank: Unknown
timestamp: October 23, 2024, 10:48:20 am
content: Looks like PCI version of Riva TNT or something similar of that time. Fan should be blowing into the heatsink. Buying fan by itself is easy, I guess it's 60x60mm and rated for 5V. Finding one with appropriate connector complicates it quite a bit. I'd probably solder it directly to PCB instead of connector if could not crimp it or replace the wires (usually can be soldered on the fan side after lifting the sticker)

author: indeterminate
author_rank: Regular Contributor
timestamp: October 23, 2024, 10:54:12 am
content: It looks like the fan was secured to the heat sink with a couple of self tapers into the heat sink fins.measure the distance between the thred marks and see if one of the following will match uphttps://au.mouser.com/c/thermal-management/fans-blowers/?height=35%20mm~~37.6%20mm&width=35%20mm~~36%20mm&instock=y&rp=thermal-management%2Ffans-blowers%7C~Height%7C~Widthyou will need to solder a plug onand chk that it is 5v before you order the fan as it could be 12v

author: Ranayna
author_rank: Super Contributor
timestamp: October 23, 2024, 11:11:05 am
content: Quote from: indeterminate on October 23, 2024, 10:54:12 amGood eye, yes, the screw marks are well visible. I missed them.

author: Halcyon
author_rank: Unknown
timestamp: October 23, 2024, 11:16:25 am
content: Quote from: Ranayna on October 23, 2024, 11:11:05 amYep. Pretty common for early hardware.

author: Halcyon
author_rank: Unknown
timestamp: October 23, 2024, 11:18:39 am
content: Quote from: wraper on October 23, 2024, 10:48:20 amClose. It's a Voodoo Banshee card.

author: Circlotron
author_rank: Super Contributor
timestamp: October 23, 2024, 11:24:59 am
content: Quote from: Halcyon on October 23, 2024, 09:08:34 amProviding the rate of airflow is the same in both cases, I imagine blowing air toward the heatsink would be more effective because the air leaving the fan would be more turbulent compared to air working its way through the heatsink on the way to the fan. Just my gut feeling. No supporting data.

author: Halcyon
author_rank: Unknown
timestamp: October 23, 2024, 11:28:32 am
content: Quote from: Circlotron on October 23, 2024, 11:24:59 amThis is what I'm wondering. I think having two PCI cards butted up against each other in adjacent slots is asking a bit much. Either I'm struggling to suck enough air to blow towards the heatsink, or I'm blowing hot air directly onto the back of another card. I'm resigned to the fact I'm probably going to have to leave an empty slot in between.

author: Nominal Animal
author_rank: Super Contributor
timestamp: October 23, 2024, 12:15:48 pm
content: If you measure the diagonal center-to-center distance between the mounting screws, is it 54.6mm or 59mm?Also, the fan connector looks suspiciously like a standard 2.54mm JST XH connector, which would be extremely common for 2-pin fans; are you sure the pin center-to-center distance is 3mm and not 2.54mm? If it is a JST XH connector, you can reuse a standard 3-pin fan, by depinning the connector (the yellow wire is the unused tach output), and using a 2-pin JST XH instead of the standard 3-pin one.Back in the era where that card was common, many chipsets used a 38mm × 38mm heatsink with two diagonal screws at 54.6mm or 59mm center-to-center distance, with option for a 40mm × 40mm × 10mm-20mm fan; Akasa fans were particularly common.Enzotech CNB-S1 or CNB-S1L is an excellent replacement, because the fins are round, allowing for more cooling options, including laterally in the plane of the video card. Then, if you have room at the end of the video card, you can use a rectangular cone and a much larger fan, to push air across the heatsink, towards the video card connector end. This will increase the ambient temperature within the enclosure (because the air cannot exhaust from the connectors), so you should ensure sufficient airflow through the enclosure. If you use the longer pin version, you can (laboriously!) sand down the pins to whatever length best suits your needs.

author: wraper
author_rank: Unknown
timestamp: October 23, 2024, 12:22:12 pm
content: Quote from: Nominal Animal on October 23, 2024, 12:15:48 pm3 pin computer fans fans use connector that is very different from JST XH.

author: Nominal Animal
author_rank: Super Contributor
timestamp: October 23, 2024, 03:27:32 pm
content: Quote from: wraper on October 23, 2024, 12:22:12 pmMolex KK 2695 series,Molex 22013037, to be specific; with the corresponding two-pin connector beingMolex 22013027. The male PCB connector is not shrouded, with just a friction "tongue" on one long side. The connector in the shown image definitely looks like JST XH 2-pin female one, or some 3mm pitch clone.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 23, 2024, 10:56:45 pm
content: Quote from: Halcyon on October 23, 2024, 09:08:34 amI have just recently made cooling for fx5500. I will proceed from the fact that the modification is done for yourself. The very first thing you should start with is to lower the chip supply voltage, and this is mandatory and cannot be skipped. On your board, I see LT1084. You do not need to unsolder anything, just put an additional resistor from the adj pin to ground. Having selected a resistor, the next step is to explore the possibility of installing a high radiator. For fx5500, I managed to clear the adjacent slots, and I used this radiator (link).https://aliexpress.com/item/4000050337687.htmlIn the case of mx400, I did not have enough space, but the back surface of the board was flat - I glued an additional large radiator on the back side. Sometimes the height of adjacent elements allows you to put a wide radiator on the chip. Now choosing a fan. Mostly, a fan with a 40 mm fin is used, it is extremely difficult to find a quiet one. The quietest fan of this type was found on the Intel GCLF board, Jamicon fans of exactly the same type were bought (photo from the Internet). However, it turned out later that the ball bearings are all of low quality. It turned out to be more effective to have a fan on a plain bearing, lubricated with black LSM grease (with disassembly and obvious smearing). The next step is to select a resistor in series with the fan. As it turned out, this is always a 100 ohm resistor, you can skip the selection and immediately install a 100 ohm 0.5 W. And you don't need to cut the original fan wires, the soldering points are accessible by slightly peeling back the sticker.

author: Halcyon
author_rank: Unknown
timestamp: October 23, 2024, 10:59:48 pm
content: Appreciate the advice Postal2, however my intention is to keep this card as stock as possible. I'll only be adding a fan, with no other modifications. The only other thing I'll probably do is replace the heatsink compound (if it's not glued on like some other 3dfx models).

author: Postal2
author_rank: Frequent Contributor
timestamp: October 23, 2024, 11:16:23 pm
content: Quote from: Halcyon on October 23, 2024, 10:59:48 pmOK, see above how.Quote from: Halcyon on October 23, 2024, 10:59:48 pmThis is unnecessary and unnecessary. Even mentioning it in relation to heating at the Pentium mmx level looks unprofessional.

author: nctnico
author_rank: Super Contributor
timestamp: October 23, 2024, 11:47:57 pm
content: I'd go for the lowest power, lowest RPM fan I could find. I don't think the direction of airflow makes any difference as the blades are close to the fins anyway. Also keep in mind that the cooling effect degrades exponentially with the amount of airflow. Or put differently, a little bit of of airflow directly on a heatsink makes a huge difference already.I'd be more concerned putting the videocard in a place where there is airflow. Back in the days when I build my own PCs, I would leave a cover plate from a slot to allow airflow over the videocard. BTW, my current PC (Dell workstation) has a passively cooled videocard and perforated cover plates for empty slots to allow airflow.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 24, 2024, 12:01:32 am
content: Quote from: nctnico on October 23, 2024, 11:47:57 pmNow experienced developers will read your conclusions - and we will get tablets and smartphones in the form of a colander, which must be waved to cool.

author: themadhippy
author_rank: Super Contributor
timestamp: October 24, 2024, 12:20:11 am
content: Quoteif thats the case hows about using that slot for a cooler

author: Someone
author_rank: Super Contributor
timestamp: October 24, 2024, 12:24:34 am
content: Quote from: themadhippy on October 24, 2024, 12:20:11 amThat was a thing back in the day. Remove fans from object and add fans next to it to flow at least more air over it.

author: Halcyon
author_rank: Unknown
timestamp: October 24, 2024, 12:40:50 am
content: Quote from: Postal2 on October 23, 2024, 11:16:23 pmNot entirely sure what you mean by this? Heatsink compound doesn't last forever and should be replaced from time to time.

author: Halcyon
author_rank: Unknown
timestamp: October 24, 2024, 12:53:43 am
content: Quote from: nctnico on October 23, 2024, 11:47:57 pmI think needs *something*. I believe, and I could be wrong, but this particular card did actually come with a fan from the factory as they do run quite hot. I picked this up second hand and the fan was missing.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 24, 2024, 12:56:46 am
content: Quote from: Halcyon on October 24, 2024, 12:40:50 amYes, if a high heat removal rate is required. If someone talks about changing the thermal interface on a plastic chip like mx400 - then most likely it is a schoolboy.If you open the DVD drive, you will see thermal pads there. Open the oldest drive and determine if they need to be replaced.

author: Halcyon
author_rank: Unknown
timestamp: October 24, 2024, 02:06:49 am
content: Quote from: Postal2 on October 24, 2024, 12:56:46 amI tend to disagree. I've been building and fixing computers for over 25 years. As a matter of course, if the device is old and heatsink is easy to remove, I'll generally give is a good clean and renew the thermal compound. For the sake of a few cents and 10 minutes work, it's worth it, even if it's just for peace of mind. Very old compound can dry out and no longer form a good bond, which means it's less effective. Of course if chip itself doesn't really get that hot, I don't bother, but for CPUs and graphics cards, almost certainly I would do this.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 24, 2024, 02:20:30 am
content: Quote from: Halcyon on October 24, 2024, 02:06:49 amI fully understand that some people get pleasure from certain actions. This has nothing to do with expediency.Quote from: Halcyon on October 24, 2024, 02:06:49 amThis is a very old card on a plastic chip, originally without a fan, which you wanted to install. Now you are talking about replacing the thermal interface on it. I also like to wipe everything with alcohol. It brings some finality to my head, I understand that.https://www.techpowerup.com/gpu-specs/voodoo-banshee-pci-16-mb.c3562

author: thermistor-guy
author_rank: Frequent Contributor
timestamp: October 24, 2024, 04:12:19 am
content: Quote from: Halcyon on October 23, 2024, 09:08:34 amThis is similar to a common problem in the DIY NAS community. DIYers are using PCIe HBAs (Host Bus Adapters) from serversin PCs, to connect 8, 16, or more or internal SATA drives. A common HBA is the LSI 9211-8i.In a PC, the HBAs run hot (too hot), since they were intended to work in server racks with serious air flow. The cheap solutionis to add a fan. So users are adding fans to the heatsinks, with mounting screws fitting in between heatsink fins. A common add-onfan is the Noctua NF-A4X20-FLX. The fan usually means keeping a PCIe slot empty, which some uses are willing to do.There is a company that makes PCIe fansinks - a low profile combination of heatsink plus fan:https://radianheatsinks.com/product-category/pcie-fansink/Radian might have a product that suits your needs. Or maybe it can point you to an old product that is no longer listed, but is stillavailable on Ebay somewhere.A search of DIY NAS forums, for HBA cooling solutions, might also turn up something you can use.