XPS 8950, replace CPU myself?

Question

Hi

I have a Dell XPS 8950 which is two years old (so out of warranty), and over the past week it's slowed to a crawl. I've run the UserBenchmark tests and the results say that my CPU (i9-12900K CPU @ 3.20GHz) is running at 14% speed. I've reinstalled Windows and reset the BIOS to the default options without success. What should I do now? Can I replace the CPU myself (the machine is water cooled, which may present a problem)? Is there anything special about the Dell motherboard (or anything else) that prevents me from replacing it with an identical new CPU from Intel? Alternatively, what's the best way to get it checked/repaired?

Thanks

W1tchseason · Accepted Answer

When I ran the CMOS hard reset according to the instructions, I got a message saying that it had succeeded - but no changes were made.

This morning I decided to do it the 'brutal' way - unplugging the machine and removing the CMOS battery. Left it a few minutes, put in a new battery, fired up the PC... and *still* no change. System date and time intact, booted straight to Windows.

Then I thought - nothing to lose, reflash the BIOS. Went to the Dell website, downloaded the BIOS patch on the XPS website, copied it to a USB stick, rebooted from it and flashed the BIOS. Got warnings about 'are you sure you want to overwrite the BIOS with an older version?' and I said Yes. Go ahead.

So it did its thing, rebooted, and...

I HAVE MY NINJA PC BACK! Everything running fine, UserBenchmark tells me everything is outstanding. CPU running at max power again.

So it seems that the problem was caused by a BIOS update. I've never knowingly done that, perhaps a recent Windows update did something to the BIOS?

Either way, it's all good now. Thank you so much for your help :-)

redxps630 · Accepted Answer

a bios update that was very buggy which caused power limit of cpu and severe throttling of cpu. It even resisted RTC reset. That is how buggy this bios version was.

This case in point shows that cpu is good but bios can cripple it.

redxps630 · Answer

Most likely the issue is not due to an assumed defective or damaged cpu. Replacing cpu w a new one will probably not solve your issue. CPU almost never dies (except some newer 13/14th gen cpu that have premature degradation)

you can try run HWMonitor to find out cpu temp. If the cpu was over heating it could slow down.

Next run Dell pre boot diagnostic test (PSA). I presume cpu will pass.

Next run free user benchmark test to compare your cpu to peers.

You need to uncover the underlying culprit of slow cpu run frequency than pointing finger at a bad cpu (most likely not bad).

W1tchseason · Answer

@redxps630​ Hi, thanks for your reply. I have run the PSA and everything passed OK. I also ran User Benchmark, results were: UserBenchmarks: Game 19%, Desk 32%, Work 19% CPU: Intel Core i9-12900K - 14.2% GPU: Nvidia RTX 3080 - 106.3% SSD: Samsung 860 Evo 2TB - 54.7% SSD: Pc801 NVMe SK hynix 1TB - 151.8% RAM: Unknown HMCG78MEBUA081N 2x16GB - 42.8% MBD: Dell XPS 8950 I will run HWMonitor tomorrow (I have to go out now). Thanks again.

redxps630 · Answer

Next time when you run user benchmark compare your cpu to others same cpu spec and see where you are on a bell curve. And you can run this test for as many times as you want to get an averaged performance test.

redxps630 · Answer

14.2%. seems way below average

Average Bench: 117% (33rd of 1466)

Re: over the past week it's slowed to a crawl. reset the BIOS to the default options

I think more likely your CMOs has corrupted settings which underclocks your cpu. Check task manager>performance for cpu idle and run frequency

Soft reset bios options within bios would not help. You should probably try a hard reset (RTC reset) of CMOs.

https://www.dell.com/support/manuals/en-us/xps-8950-desktop/xps-8950-service-manual/real-time-clock-rtc-reset?guid=guid-87b228f9-c91a-4409-88f0-7099a90421a9&lang=en-us#:~:text=You%20can%20initiate%20the%20RTC%20reset%20on,hold%20the%20power%20button%20for%2030%20seconds.

W1tchseason · Answer

@redxps630​ Hi again, and thanks. I followed the instructions on that page and it seemed to complete successfully, but I'm not sure - that page says that the process will reset the date and time - but it didn't. Everything in the BIOS seems as it was before (I took screenshots of all the relevant pages and nothing seems to have changed). Does that mean that the CMOS hards reset failed - despite the 'success' message? There's no obvious change in speed either - I'm trying to run UserBenchmark again but the server is full :-(

W1tchseason · Answer

UserBenchmark gives the same results as before. And I've tried setting minimum processor power in Windows to 100% but that makes no difference. Temperature is fine.

In Task Manager, System Idle Process is between 94-98%. CPU utilization is 0%, speed is 0.38GHz but Base Speed is 3.20GHz.

I also (on Dell tech support advice) installed Windows on a different 'know good HDD' but that was even worse.

Clearly, the problem is unrelated to Windows - even when booting the machine from cold the whole process is painfully slow. I watch Dell logo being drawn on the screen (*very* slowly), and the messages and screens that normally flash by before it shows the login screen are extremely sluggish.

So - assuming no hardware fault - what could cause the CPU to run so slowly?

redxps630 · Answer

Re: Does that mean that the CMOS hards reset failed?

try RTC reset again. If settings are not reset then the RTC reset you did has not actually cleared cmos.

Re: speed is 0.38GHz

Try HWiNFO

Most throttling is either temperature related or power limit related. The HWiNFO Limit Reasons data is the best way to troubleshoot throttling problems.

HedgeFundManager · Answer

get the Intel driver and support tool It can find updates

Element115s4 · Answer

Which BIOS is bad again? I have not had one bad one with the 8950...but there is a new one out :P

W1tchseason · Answer

@Element115s4​ It was version 1.21.0 from AMI (Aptio setup). I think it must have been part of a Windows update, because I certainly didn't manually update the BIOS. It installed automatically, some time during the past two weeks.

Element115s4 · Answer

@W1tchseason​  Ah, thanks for the heads up. I am still at v1.20 so I will hold off on it then. I always use Windows for the BIOS updates and it's always optional. Dell update is nagging me about it but not Windows update which tells me it might not be ready for prime time.

RoHe · Answer

Now that PC is running better, go into BIOS setup and disable UEFI Capsule Updates. Save the change and exit setup. That should prevent Windows Update from installing any new BIOS updates. (Won't prevent SupportAssist from doing it automatically or you from doing it manually.)

Just remember that every single time BIOS does get updated, you have to open BIOS setup and disable UEFI Capsule Updates again.

BTW: Your issue doesn't necessarily mean that new BIOS is faulty. Could just have been a faulty flash update on your PC , rather than a problem with that version of BIOS.

HedgeFundManager · Answer

AFAIK UEFI updates are mostly to support new model SSD controllers which are now evolving as prices for  2TB fall again

XPS Desktops

XPS 8950, replace CPU myself?

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