The issue wasn't easy to reproduce, all standard checks and torture tests ran just fine but much more random workload crashed the unit when all cores were maxed for few seconds at a time instead (eg. during compiling). Sometimes it happened twice a day sometimes once a week.
It would only attempt to POST 1 time out of about 10 power on attempts and won't finish enough of the POST to even make it into the BIOS/UEFI setup. When it would fail to even attempt to POST it wouldn't even initialize the USB peripherals (keyboard doesn't light up).
I swapped everything (GPU, ram, power supply, etc) before getting to the point of suspecting the motherboard was faulty because it would not Q-FLASH via a USB thumb drive so I sent it in for warranty service. Since the manufacturer said the motherboard passed their quality checks there is nothing else that could be left besides the CPU.
Even given all that, I refused to believe the CPU could be the culprit until I saw the failure rate graph for AMD 5000 series processors in the article that far exceed what I figure would have been in the 0.5% range.
Live and learn I guess but it certainly adds a new fun dimension to troubleshooting because I don't exactly keep spare CPUs laying around "just in case" like I do with a spare power supply.
For me it was simple: disable C states - Stable for a week (at first it'd be weeks between crashes, then days, then daily, and at this point a couple hours) Enabled them again - crashed within an hour Disable again - Stable for a week. Flop back and fourth a handful of times in the same day.... same as above.
I can only guess that this might be something that was fixed in the mysterious "frequency voltage curve change" stepping.
My current laptop was getting uncomfortably hot when some random browser pages started pressing the cpu, after searching I noticed that the default setting was to enable some kind of "Boost Mode" (that's basically overclocking in the classic sense), disabling that made a world of difference and looking at the failure rates of the Ryzen 5000 series in the article I'm not a single bit surprised about it.
Googling the laptop family you get tons of Reddit hits, https://www.reddit.com/r/ZephyrusG14/comments/gho535/importa...
I was just trying to provide a few examples of real first hand failures. And most OCing doesn't break anything, but every once in a while you set some voltage and one part never works again, hard not to conclude it was the OC when the failure perfectly coincides. I suppose it could be coincidental, but that stretches credulity.
Another issue as an end user is I don't have the resources to prove that it was the CPU a lot of the time. I've had some laptop failures that could have been the CPU, could have been the motherboard, could have been the power supply, dunno, all I've really got is that it doesn't boot and I don't have the capacity to diagnose it due to the level of integration and inability to get replacement parts to even try to diagnose the problem. And while as a poor college student, I had the time and desire to carefully replace parts and exert maximum diagnostic effort to figure out exactly what is wrong because I can't just buy a new complete setup, not everyone goes to this level of effort, and they may not be correct.
End users really can't pick up on these trends. The data set is so noisy. Sure, the "end users" may have had suspicions about this but I've also seen communities come to consensus about certain things being broken that I had very good reason to believe were wrong and were just internet forums amplifying random loud voices being confidently and loudly wrong about things until it become "common consensus" through the power of nothing but the confident and loud error.
It took most of a year to nail that one down.
AMD didn't ask for anything besides proof of ownership once I told them disabling C states fixed it. And, 5950x's have a 5 year warranty...
PS: if they were Northwood P4's, see: https://www.overclockers.com/forums/threads/the-official-sud... (I didn't name it. I agree, terribly insensitive name)
On a 20-sided die a natural one only comes up 5% of the time.
I don't think I'm quite at having owned 40 (desktop) CPUs, but I've had failed CPUs a number of times. On an old Athlon XP 3000+ it had bad CPU cache and was able to change it from crashing repeatedly to working by disabling a large swath of the L2 cache in a bio setting. I am just now retiring a workstation that had an AMD Ryzen 5950x that was generally unstable, that would pass memtest and all the diagnostics I know how to run would pass, but about once a month would print a message on all the consoles I had open about an MCE kernel exception detected on some CPU number at random. One time I had one of those budget TriCore CPUs that had the 4th core turned on in the BIOS by accident, and that generally caused the ton of issues when I figured out it was being detected as a quad core I went in and disabled that last core and it went back to working just fine.
I'm sure at least one or two of my Intel machines failed similarly, I've had a number of dead CPUs including a few Pentium 4s back when I used to fool around with overclocking settings, and at least a few dead server chips. And I know that I've had a few systems that simply wouldn't boot even when all the parts were fresh out of the box but would when I'd swap out one part or another, and sometimes that failed part was a CPU whether it be AMD or intel.
Oh, I also get to cheat no clue how many dead Solaris CPUs I have seen! Those big Mainframe imitation systems have the ability to hot swap CPUs and it was pretty rare to have a cabinet sized computer where every piece of hardware was fully operational, at least in my role as a legacy maintainer of such things. I bet they worked much better when they rolled off the factory line.