An article on Static and Dynamic RAM.  - Page 1
Forum section: electronics / general

author: Peter Taylor
author_rank: Regular Contributor
timestamp: June 17, 2022, 02:20:02 pm
content: Static RAM is significantly faster than Dynamic RAM.Dynamic RAM is significantly cheaper to manufacture than Static RAM.I would rather pay significantly more for a fast computer with Static RAM, but as a consumer, I am not given that option.Manufacturers would rather sell me an expensive slow computer with a large profit margin, than a useful fast computer with a low profit margin.

author: rob77
author_rank: Super Contributor
timestamp: June 17, 2022, 02:35:48 pm
content: you do have static RAM in your computer it's the registers in the CPU and also the cacheand trust me you would definitely not want to pay for a 16GByte of static RAM

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: June 17, 2022, 02:44:30 pm
content: Another thing to appreciate is just how valuable the CPU's cache memory is, which speeds up tasks enormously.Additionally, the memory speed limit depends on the memory bus speed. Unless you are running memory that is a slower speed than the max bus speed, what ever the technology the ram is, the speed is governed by the speed of the memory bus.

author: Peter Taylor
author_rank: Regular Contributor
timestamp: June 17, 2022, 03:45:51 pm
content: I would rather a computer that had no DRAM. Internal or external. Static RAM also uses significantly more space. I would rather use a fast computer that used more space, and I would happily pay the price for the speed (of course this is something that I should not pay extra for. This should be standard).

author: MK14
author_rank: Super Contributor
timestamp: June 17, 2022, 03:47:21 pm
content: Is this a BOT?

author: ataradov
author_rank: Super Contributor
timestamp: June 17, 2022, 03:50:13 pm
content: If you scale SRAM to GB capacity, it will be slower than DRAM of the same capacity.And yes, I suspect this is a bot.

author: Peter Taylor
author_rank: Regular Contributor
timestamp: June 17, 2022, 03:56:24 pm
content: i am not a roooobooot

author: Bassman59
author_rank: Super Contributor
timestamp: June 17, 2022, 03:57:50 pm
content: Quote from: Peter Taylor on June 17, 2022, 03:45:51 pmSounds like you have Elon Musk-level money.

author: Peter Taylor
author_rank: Regular Contributor
timestamp: June 17, 2022, 04:01:03 pm
content: Speaking of A Space Odyssey, 2001.Quote: 'open the pod door HAL ... no Dave, I cannot do that'.

author: MK14
author_rank: Super Contributor
timestamp: June 17, 2022, 04:04:02 pm
content: Quote from: Peter Taylor on June 17, 2022, 04:01:03 pmI suspect one of three things, as well as BOT,or a returned, recently banned member,here:https://www.eevblog.com/forum/chat/i-have-found-the-answer-to-life-the-universe-and-everything/msg4191472/#msg4191472Or multi-accounting, as they expect their main account is going to get banned, anytime soon.All or most of their threads/posts, don't really seemright.

author: wraper
author_rank: Unknown
timestamp: June 17, 2022, 04:07:59 pm
content: Quote from: Peter Taylor on June 17, 2022, 03:56:24 pmYet you start multiple threads about nonsense. FYI static RAM sticks instead of DRAM makes no sense. It would be (very) extremely expensive and performance would be completely wasted due to slow interface. With current technology static RAM only makes sense within CPU as cache and which is how it is actually done.

author: Peter Taylor
author_rank: Regular Contributor
timestamp: June 17, 2022, 04:09:56 pm
content: 'Sounds like you have Elon Musk-level money'. I wish.

author: wraper
author_rank: Unknown
timestamp: June 17, 2022, 04:16:24 pm
content: Quote from: Peter Taylor on June 17, 2022, 02:20:02 pmI have a real shocker for you. Big buck corporations have no such option either.

author: Peter Taylor
author_rank: Regular Contributor
timestamp: June 17, 2022, 04:18:49 pm
content: In what possible conceivable way can SRAM be slower than DRAM, when it is about a thousand times faster ?

author: wraper
author_rank: Unknown
timestamp: June 17, 2022, 04:22:12 pm
content: The only thing I have to complain about consumer RAM, there is no ECC option as standard (but it sort of works on some consumer HW), and more often than not RAM sold with overclocked ratings.

author: MK14
author_rank: Super Contributor
timestamp: June 17, 2022, 04:32:23 pm
content: Quote from: wraper on June 17, 2022, 04:22:12 pmI think the real issue/problem, is that the vast bulk of PC (and other devices) users, probably don't know what data corruption/rot is, have never heard of ECC, or have any idea, that DRAM does (in theory and usually in practice), occasionally bit-flip (and worse), the memory contents.Hence there is no real demand or market for it, in the consumer space.Whereas, because (in at least some cases), the head of IT (and similar), orders computers for businesses, and they tend to be at least business class. It is much more common for them to go for ECC, and know/understand what it is, and why it is important/needed, in many (if not all) cases.

author: ataradov
author_rank: Super Contributor
timestamp: June 17, 2022, 04:37:34 pm
content: Quote from: Peter Taylor on June 17, 2022, 04:18:49 pmBecause SRAM cell has ~6 times the area compared to the DRAM cell. For a large capacity memory signal propagation delays would start hitting hard.Look at how much effort ges into caches in modern CPUs. L1 cache size is basically limited by the propagation delays. It will not grow any more in size.

author: wraper
author_rank: Unknown
timestamp: June 17, 2022, 04:40:34 pm
content: Quote from: MK14 on June 17, 2022, 04:32:23 pmIMHO the only major reason is that manufacturers don't want to blur the line between consumer and server/workstation HW since in latter much higher price can be set. For example Intel allows ECC on some of their consumer desktop CPUs... which are on the bottom end, so cannot cannibalize market of high priced systems.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 17, 2022, 04:41:39 pm
content: Quote from: Peter Taylor on June 17, 2022, 04:18:49 pmYou are missing the fact that technology is COMPLEX and DIFFICULT!There is no such simple concept as "DRAM is slow" and "SRAM is fast", that's a huge simplification.But in real world, bicycle wins over a Ferrari if you need to drive in a tunnel 1 meter (3 feet) wide.Similarly, each SRAM memory cell is physically large, and consumes power. You can put a million together, but if you try to put billion together, they will spread out over large area, and getting data in/out of it will slow down.Besides, DRAM is not 1000 times slower at all. DRAM has pretty decent burst read speed - you can read consecutive bytes in order very fast.Computer scientists and engineers have worked out pretty decently optimized compromise, which utilizes the good features of SRAM and DRAM, by combining them together. DRAM provides bulk of the memory - because a lot of memory is needed - and SRAM cache helps increase performance.

author: ebastler
author_rank: Super Contributor
timestamp: June 17, 2022, 04:49:18 pm
content: Quote from: Peter Taylor on June 17, 2022, 03:56:24 pmAlright, I believe you. Most likely you are for real, posting under your real name, and you have recently established "Pete's Electronic Workshop" in Queensland, as you stated in some other post. Based on your posting activity here, the business is not keeping you fully occupied yet -- which is fine, of course.But what do you expect to gain by posting these lecturing "articles" here? We have seen nonsensical ones, technically wrong ones, and now a blindingly obvious one. I have no idea what you hope to achieve by these, but they are not going to get you any "streed cred" on this forum.If your intent should be to establish yourself as a valued member of the forum, I recommend that you look for posts from others where you can provide meaningful answers. That's where you can add value. The declamatory "articles" don't help anyone, and certainly don't help yourself.

author: MK14
author_rank: Super Contributor
timestamp: June 17, 2022, 05:03:48 pm
content: Quote from: wraper on June 17, 2022, 04:40:34 pmI agree, that is a significant factor. But is still only part of the story.If I understand things correctly. The original IBM PCs (at some point), did actually have some kind of parity memory as standard, because of perceived bit-flip issues, with ancient technology DRAM chips of the time, where a theory of Alpha-radiation in the chip packaging (possibly cosmic-rays, as well), were/would cause a number of bit-flips.

author: Zoli
author_rank: Frequent Contributor
timestamp: June 17, 2022, 05:10:58 pm
content: "There is always a well-known solution to every human problem—neat, plausible, and wrong" - Murphy.In this case: random access vs sustained transfer - and all the working tricks to hide the difference. Make a bank of SRAM in the same way as is done with DRAM - now you have 9-12-12-23(access) instead of 16-20-20-38(access) at the 1000Xtimes of the price(all of the numbers are fictional, but in the proper ballpark) to start - is worth?Of course, if you manage to overtake the whole DRAM market, you can supply those 9-12-12-23 SRAM sticks @6Xcurrent price

author: Benta
author_rank: Super Contributor
timestamp: June 17, 2022, 07:33:34 pm
content: Quote from: Zoli on June 17, 2022, 05:10:58 pmWrong: H. L. Mencken, 1920. Later paraphrased by others (not Murphy, though).

author: Zoli
author_rank: Frequent Contributor
timestamp: June 17, 2022, 07:53:09 pm
content: Quote from: Benta on June 17, 2022, 07:33:34 pmYou've caught me; I was lazy.Now, do you have anything to add to the SRAM vs. DRAM discussion?

author: SiliconWizard
author_rank: Super Contributor
timestamp: June 17, 2022, 08:05:34 pm
content: Quote from: ataradov on June 17, 2022, 03:50:13 pmYup. And:* The cost (area) of several GB of SRAM, the OP probably doesn't want to know. Completely unpractical.* With modern multi-level caching schemes, this would make almost no difference whatsoever, at least for general-purpose computing.Quote from: ataradov on June 17, 2022, 03:50:13 pmI dunno.

author: Benta
author_rank: Super Contributor
timestamp: June 17, 2022, 08:11:49 pm
content: Quote from: Zoli on June 17, 2022, 07:53:09 pmNo. Having seen other threads from the OP, not my thing.

author: Someone
author_rank: Super Contributor
timestamp: June 17, 2022, 11:56:45 pm
content: Quote from: Peter Taylor on June 17, 2022, 02:20:02 pmWell actually you are:https://www.digitaltrends.com/computing/amd-teases-3d-v-cache-chip-performance/huge globs of sram, that add very little to real world performance, which is why there isn't a market for consumer computers exclusively running on sram.Build your own system! Intel offer you a choice of HBM DRAM or direct connect SRAM:https://www.intel.com/content/www/us/en/products/details/fpga/agilex/i-series.htmlhttps://www.intel.com/content/www/us/en/products/details/fpga/agilex/m-series.html

author: BrianHG
author_rank: Super Contributor
timestamp: June 18, 2022, 12:39:58 am
content: In dram, each bank, for example: there are 8 of them in each DDR3 ram chip, has the entire column address space as static ram.Proper interleaving the read/write access, if you operate in a forward or backward in a near sequential manner, other than the initial setup delay, your reads and writes should be at full clock speed, uninterrupted as if it were static ram.Since CPU code hops all over the place, it takes smart compilers and coding techniques to attempt to maintain such continuous access which often fails. Large cache and branch prediction is designed to help overcome this. Video cards usually have architectures designed to help improve sequential access of dynamic ram.Huge static ram as others here have said just ends up being slower due to layout and silicon area per bit size.

author: SiliconWizard
author_rank: Super Contributor
timestamp: June 18, 2022, 01:09:31 am
content: Very fast SRAM above "small" sizes is also accessed synchronously in bursts anyway, having thus the same access constraints as DRAM. Just that they don't need refresh.

author: mawyatt
author_rank: Super Contributor
timestamp: June 18, 2022, 01:51:35 am
content: Quote from: MK14 on June 17, 2022, 05:03:48 pmRemember the issue was with the ceramic used in the memory package. Japan used Kyrocera ceramic packages and these showed no signs of "bit-flips", whereas all the US based suppliers used packages that had 3M ceramic and had "bit-flip" issues. Many folks jumped on the bandwagon saying US chip suppliers were inferior to Japan based upon this issue.Intel found the source as slightly radioactive ceramic from 3M that caused the issue and instead of Intel keeping this to themselves and profiting, they let everyone know, including their competitors!!Anyway, 3M cleaned up their ceramic and this issue was resolved.Best,

author: MK14
author_rank: Super Contributor
timestamp: June 18, 2022, 05:31:58 am
content: Quote from: mawyatt on June 18, 2022, 01:51:35 amIn the old days, Intel was a pretty decent company, in many (NOT all, a good example is the 4004, where one of its original creators was ignored and left out of acknowledgement of their historic achievements, because of very badly annoying Intel, when they left it, in bad terms. Probablyhttps://en.wikipedia.org/wiki/Federico_Fagginand his creating Zilog, really upset Intel. Although I fully accept Intel being really annoyed at the Zilog issue, and the Z80 "unfairly" stealing the limelight/profits/8080. Intel should still have been truthful about who created/designed etc, the 4004, and onwards.).In later (recent years), I hear less and less, about how nice/honorable Intel is as a business. But don't get me wrong, they still seem like a decent company, over-all. Except perhaps chasing profits too keenly, rather than doing what is best for final consumers of Intels products (such as NOT allowing/enabling ECC memory capabilities, on their cheaper CPUs, even if it is actually present on the chip. Arguably, ECC should be enabled for EVERYONE, as it is of potential benefit to almost all users, even if your average joe probably, doesn't know what it is, or realize that they would benefit from it, due to less silent/secret/hidden data corruption).Old DRAM chips, especially from the 1980/1990s (in my experience), but other years as well. Seem to sometimes, just break (whereas e.g. CPUs, very rarely break, unless badly abused). Even if just left, without being used. I sometimes wonder why that might be. Radiation from the package and/or background and/or cosmic-rays, possibly damaging the floating-gate (or whatever it should be called), mosfet (capacitor), and then damaging it in some way. As, perhaps it is NOT configured to 'dissipate' the excess charge/voltage, in a safe (undamaging) way, like most other semi-conductors, typically *might*.TL;DRDRAMs apparently being excessively sensitive to damage/aging/destruction due to radiation from various sources. Making them age much less well, compared to most other semiconductor ICs.I suppose it could also be because DRAMs are really a (almost Frankenstein) mixture of digital and analogue, on the same chip. Whereas most desktop CPUs, are mostly fully digital. Which might compromise the processes to make those ICs, especially in huge bulk numbers and at very competitively low cost to the consumer (i.e. maybe not enough process steps, are carried out, to ensure the best chips and/or cost savings), have reduced their reliability, especially for the longer term.Perhaps tiny changes inside the chip as it ages, are enough to 'damage/break' it, unlike CPUs, whose wide tolerance, big safety margins, and strict digital operation (not on all of them, as some of them are not truly static devices, but need minimal clocking, due to dynamic processes on some bits, to save transistors/chip area, and hence reduce costs), mean a CPU can carry on working, even if there are minorchanges, in the IC, as it ages.I've sometimes searched for answers (I suspect, but I'm NOT sure), but usually draw a blank. Either because people don't know, or it is an industry/trade secret (the DRAM industry, seems extremely secretive, in modern times, i.e. after the DRAM industry left America), kept to the highly competitive DRAM memory suppliers.

author: MK14
author_rank: Super Contributor
timestamp: June 18, 2022, 05:57:46 am
content: Quote from: MK14 on June 18, 2022, 05:31:58 amI shouldn't really answer my own post (question), but on reflection, I will try to. The question seems to boil down to, why do DRAMs seem to break much more often then CPUs and other chips.Maybe the answer is that it is because a potentially typically PCs (going back lots of years), would have usually had just one main CPU, such as an Intel or AMD one. Whereas the main memory, would (perhaps), of consisted of 4 occupied memory slots, with each memory DRAM stick, having (maybe) 8 DRAM chips, on both sides, making a total of 16 DRAM chips per DRAM memory stick (more if parity/ECC type).So there could have been 4 x memory DRAM sticks = 8 sides, with perhaps 8 DRAMs per side (memory capacity of DRAM chips at the time, and its pricing, dependent).= 4 (slots) x 2 (sides per DRAM stick) x 8 (per side) = 64 DRAM chips per PC.So, assuming (pretending) DRAM chips and CPUs have exactly the same reliability and life-expectancy per chip. DRAM failures would be x64 times more likely to result in a failure of a PC, compared to CPUs, which there is typically only one off (ignoring all the various secondary CPUs, all over the place, potentially in PCs, such as the keyboard).Or x32 or even x16, depending on how many DRAMs are present in the PCs main memory e.g. only 2 slots used and/or less than 8 DRAMs per side. Graphics typically might also have its own DRAM chips (but I'm ignoring that fact), especially if a separate part of the PC (graphics card), as opposed to iGPUs.