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July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

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Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#181

Post by hellotomyrars »

giantg2 wrote: post #112
Dylan16807 wrote: post #91

Earlier quoted context omitted.

> Like look at this 20 core processor! Oh wait, it's really an 8 core when it comes to performance. The E cores are about half as fast as the P cores depending on use case, at about 30% of the size. If you have a program that can use more than 8 cores, then that 8P+12E CPU should approach a 14P CPU in speed. (And if it can't use more than 8 cores then P versus E doesn't matter.) (Or if you meant 4P+16E then I don't t…

Yeah, the 20 core Intels are benchmarking about the same as the 12 core AMD X3Ds. But many people just see 20>12. Either one is more than fine for most people. "Oh wait, it's really an 8 core when it comes to performance [cores]". So yes, should not be an 8 core all together, but like you said about 14 cores, or 12 with the 3D cache. "And I doubt those cores have a higher clock." I'm not sure what we're comparing the…

It’s kind of funny and reminiscent of the AMD bulldozer days where they had a ton of cores compared to the contemporary Intel chips, especially at low/mid price points but the AMD chips were laughably underwhelming for single core performance which was even more important then.

I can’t speak to the Intel chips because I’ve been out of the Intel game for a long time but my 5700X3D does seem to happily run all cores at max clock speed.

Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#182

Post by gwbas1c »

nequo wrote: post #179
gwbas1c wrote: post #164

Earlier quoted context omitted.

It's most likely both a hardware issue and a microcode issue. Making CPUs is kind-of like sorting eggs. When they're made, they all have slightly different characteristics and get placed into bins (IE, "binned") based on how they meet the specs. To oversimplify, the cough "better" chips are sold at higher prices because they can run at higher clock speeds and/or handle higher voltages. If there's a spec of dust on th…

> If there's a spec of dust on the die, a feature gets turned off and the chip is sold for a lower price. Do you mean that if a 13900KS CPU has a manufacturing defect, it gets downgraded and sold as 13900F or something else according to the nature of the defect?

It's been almost 20 years since I worked in the industry, so I don't want to make assumptions about specific products.

When I was in the industry, it would be things like disabling caches, disabling cores, ect. I don't remember specific products, though.

Likewise, some die can handle higher voltages, clock speeds, ect.

Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#183

Post by ploxiln »

jfindley wrote: post #144
phire wrote: post #100

I find it hard to believe that it actually is a microcode issue. Mostly because Intel has way too much motivation to pass it off as a microcode issue, as they can fix a microcode issue for free, by pushing out a patch. If it's an actual hardware issue, then Intel will be forced to actually recall all the faulty CPUs, which could cost them billions. The other reason, is that it took them way too long to give details.…

The months of R&D to create a workaround could simply be because the subset of motherboards which trigger this issue are doing something borderline/unexpected with their voltage management, and finding a workaround for that behaviour in CPU microcode is non-trivial. Not all motherboard models appear to trigger the fault, which suggests that motherboard behaviour is at least a contributing factor to the problem.

I think this issue was sort of cracked-open and popularized recently by this particular video from Level1Techs: https://www.youtube.com/watch?v=QzHcrbT5D_Y

Towards the middle of the video it brings up some very interesting evidence, from online game server farms that use 13900 and 14900 variants for their high single-core performance for the cost, but with server-grade motherboards and chipsets that do not do any overclocking, and would be considered "conservative". But these environments show a very high statistical failure rate for these particular CPU models. This suggests that some high percentage of CPUs produced are affected, and it's long run-time over which the problem can develop, not just enthusiast/gamer motherboards pushing high power levels.

Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#184

Post by Dylan16807 »

ComputerGuru wrote: post #161
Dylan16807 wrote: post #96

Earlier quoted context omitted.

Or if you use a single queue... which I would expect to be the default. Blindly dividing work units across cores sounds like a terrible strategy for a general program that's sharing those cores with who-knows-what.

It’s a common strategy for small tasks where the overhead of dispatching the task greatly exceeds the computation of it. It’s also a better way to maximize L1/L2 cache hit rates by improving memory locality. Eg you have 100M rows and you want to cluster them by a distance function (naively), running dist(arr[i], arr[j]) is crazy fast, the problem is just that you have so many of them. It is faster to run it on one co…

It has always been a bad idea to dispatch so naively and dispatch to the same number of threads as you have cores. What if a couple cores are busy, and you spend almost twice as much time as you need waiting for the calculation to finish? I don't know how much software does that, and most of it can be easily fixed to dispatch half a million rows at a time and get better performance on all computers.

Also on current CPUs it'll be affected by hyperthreading and launch 28 threads, which would probably work out pretty well overall.

Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#185

Post by aruametello »

SushiHippie wrote: post #138
amiga-workbench wrote: post #79

Earlier quoted context omitted.

I'm also very happy with my 5800X3D, it was wonderful value back when AM5 had just released and DDR5/Motherboards still cost an arm and a leg. The energy efficiency is much appreciated in the UK with our absurd price of electricity.

Same, in my BIOS I can activate a "ECO Mode", which lets me decide if I want to run my 7950x on full 170W TDP, 105W TDP or 60W TDP. I benchmarked it, the difference between 170 and 105 is basically zero, and the difference to 60W is just a few percent of a performance hit, but way worth it, as it's ~0.3€/kWh over here.

(if you are running windows)

you might want to check a tool called PBO2Tunner (https://www.cybermania.ws/apps/pbo2-tuner/), you can tweak values like EDC,TDC and PPT (power limit) from the GUI, and it also accepts command line commands so you can automate those tasks.

I made scripts that "cap" the power consumption of the cpu based on what applications are running. (i.e. only going all in on certain games, dynamically swaping between 65-90-120-180w handmade profiles)

i made with power saving in mind given the idle power consumption is rather high on modern ryzens.

edit: actually made a mistake given that PBO2Tunner is for Zen3 cpus, and you mentioned Zen4.

Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#186

Post by BeeOnRope »

phire wrote: post #130
RedShift1 wrote: post #121

Earlier quoted context omitted.

As I understand it, there are multiple voltages inside the CPU, so just monitoring the motherboard VRM won't cut it. That said I too am very skeptical. I just issued a moratorium on the purchase of anything Intel 13th/14th gen in our company and waiting for some actual proof that the issue is fully resolved.

It's complicated. On Raptor lake, there are a few integrated voltage regulators to which provide new voltages for specialised uses (like the E core's L2 cache, parts of DDR memory IO, PCI-E IO), but the current draw on those regulators is pretty low. The bulk of the power comes directly from motherboard VRMs on one of several rails with no internal regulation. Most of the power draw is grouped onto just two rails, Vc…

What's special about the E core's L2 cache such that it gets on-chip regulated voltage?

Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#187

Post by aruametello »

happosai wrote: post #163
weberer wrote: post #137

Earlier quoted context omitted.

Torvalds or the Youtube guy?

Yes

I can imagine both will bash intel a bit.

"Linus Tech Tips" for the gaming crowd situation (loss of "paid for" premium performance) and Torvalds for the hardware vendor lack of transparency with the community.

Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#188

Post by burnte »

yencabulator wrote: post #172
burnte wrote: post #169

Earlier quoted context omitted.

> I find it hard to believe that it actually is a microcode issue. They learned a lot from the Pentium disaster, even if it's a hardware issue, they can address it with microcode at least, which is just as good.

Except normally the result of a microcode workaround is that the chip no longer performs at its claimed/previously-measured level. Not "as good" by any standard. For example, Intel CPU + Spectre mitigation is not "as good" as a CPU that didn't have the vulnerability in the first place.

Microcode changes don't have to affect performance negatively. Do you have any evidence this one will? If it's a voltage algorithm failure, then I would expect that they could run it as advertised with corrected microcode. Unstable power is a massive issue for electronics like this and I have no problem believing their explanation. Bad power causes all sorts of weird issues.

Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#189

Post by cdchn »

I built a system last fall with an i9-13900K and have been having the weirdest crashing problems with certain games that I never had problems with before. NEVER been able to track it down, no thermal issues, no overclocking, all updated drivers and BIOS. Maybe this is finally the answer I've been looking for.

Re: July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

#190

Post by yencabulator »

burnte wrote: post #188
yencabulator wrote: post #172

Earlier quoted context omitted.

Except normally the result of a microcode workaround is that the chip no longer performs at its claimed/previously-measured level. Not "as good" by any standard. For example, Intel CPU + Spectre mitigation is not "as good" as a CPU that didn't have the vulnerability in the first place.

Microcode changes don't have to affect performance negatively. Do you have any evidence this one will? If it's a voltage algorithm failure, then I would expect that they could run it as advertised with corrected microcode. Unstable power is a massive issue for electronics like this and I have no problem believing their explanation. Bad power causes all sorts of weird issues.

If it was a microcode bug to begin with, fixing the bug wouldn't need to degrade performance. If it was e.g. a bad sensor, that you can "correct" well enough by postprocessing, it doesn't need to degrade performance. But if it's essentially incorrect binning -- the hardware can't function as they thought it would, use microcode to limit e.g. voltage to the range where it works right -- then that will degrade performance.
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