[Somewhat resolved] CPUID of my 4790K is broken? WTF

[UltimateByte]

Hi,

 

Something really weird that I never experienced in many years of practice happened to my Intel I7 4790K.

It seems so rare that I can't even find anyone with the same issue using Google, and my posts on French forums basically had no answer because nobody knows what the heck is going on.

The most trustworthy explanation being that the CPU is starting to die.

 

Long story short

I had a 4790K CPU working well, then it did some momentary crap having one core warmer than others which I solved by resetting CMOS settings and the name suddently stopped being fully displayed in the BIOS and every software. So either there is a way to repair that, either not.

 

Before you come with your suggestions, please make sure you read what I tried already because I tried a lot of things.

 

The problem in details

One part of the CPU name, the one containing working frequency which I believe is stored into the CPUID totally disappeared.

It results in missing information basically everywhere: in the BIOS, in hardware information softwares, in Windows, even in Linux (cat /proc/cpuinfo won't show the CPU name) and in Benchmarks that won't be validated.

The CPU is working perfectly fine other than that, but it's not a good sign and if it's becoming defective and there is no solution, then I will have to replace it.

 

Where does the CPU comes from

This is a second hand delided CPU with a light overclocking and speedstep enabled (wasn't before but gotta reduce the electricity bill) and a light OC@4,6Ghz, which has been running at very decent temperatures, 80°C peak during OCCT testing. It was previously cooled using a Thermalright Silver Arrow, and now using a Be Quiet Silent Loop 360.

 

Symptoms

- Around a month ago, I had a suddent isuse where Core 0 was 35°C warmer than others for no reason. I resolved the issue by doing a clear CMOS.

I believe this is the moment when the CPU lost its CPUID information because:

- After that, I noticed that 3DMark was unable to validate the result because it doesn't detect the CPU properly: https://www.3dmark.com/3dm/26385270? while I was able to run proper benchmarks with the same CPU before https://www.3dmark.com/spy/2384642

- Geekbench has the same issue : Now it is unable to detect the CPU and shows  a Pentium II/III https://browser.geekbench.com/v4/cpu/8190856 while it didn't before https://browser.geekbench.com/v4/cpu/3964381

- The BIOS doesn't show the CPU name and frequency, but other than that, all stepping and other information as well as voltages are correct.

- Windows won't detect the CPU name neither, both in computer details and device manager.

- Basic displays of CPU-Z and HWInfo show no issues at all, but the data export from CPU-Z shows missing information

 

My diagnostics

While I'm not 100% sure, I think this issue was not here before, especially thanks to my old benchmark links that showed proper information, unless 3DMark and Geekbench now use different ways of telling which CPU this is. Unfortunately, I didn't dig into this before because CPU-Z showed proper information at first glance, so I had no reason to.

 

Using a spare Celeron I have handy (used it in a home NAS), I checked if it wasn't a motherboard issue by swapping the CPUs and using the CPU-Z export function.

This test was very relevant because I found that there was missing entry in the CPUID: The "Specification" field was empty.

You can download CPU-Z exports here https://cloud.lrob.fr/index.php/s/VWrxyzzNoi5zJsL

 

What I already tried

I also tried many other things that didn't lead to any solution, including:

- Removing CPU drivers from windows on each thread and try forcing the proper one, but still shows "Uknown device" 

- Reset factory (aka "optimal") motherboard settings, both within the BIOS and by removing the battery

- Trying with another CPU (celeron) to see if it had proper CPU info, and it had, so it doesn't seem to come from the motherboard

- Modifying my BIOS to contain the latest Intel microcode and flashing it

 

Lastly, I will try putting my CPU in a friend's PC to check if it detects the CPU properly, but my guess is it won't.

 

My request

If anyone here has any idea, any clue on how to resolve that issue or just wants to show some compassion, please share on this thread!
TBH, I'm already on my way to getting a new second hand 4790K but I'd still like to save this one...

 

Thanks!

 

Screenshots

 

Aida64 showing missing information

 

With a Celeron, the BIOS shows proper CPU name information:

 

But with my 4790K, it shows nothing.

 

Windows is unable to detect the CPU

 

 

[pebble guy]

Did you buy the CPU new?

If not. Is an engineering sample? Do you have the original IHS?

[UltimateByte]

I bought it second hand, already delided, so I got no way to tell if it's the original IHS, but it's a retail IHS, not engineering sample.

What was your idea?

 

Thanks for your attention.

[TechyBen]

Check motherboard bios updates on manufactures website. It's possible it needs an update?

[UltimateByte]

@TechyBen As said in the original post, I flashed a custom version of the latest BIOS (which was already installed) with the latest Intel microcode added to it.

[TechyBen]

Custom version? I have no experience as to what that does.

[UltimateByte]

Well, because of this issue I basically modified my original BIOS using UBU and MCE just to add the latest Intel microcode, that's the only difference compared to the original.

I followed this guide https://www.win-raid.com/t154f16-Tool-Guide-News-quot-UEFI-BIOS-Updater-quot-UBU.html and it actually took just a few minutes to do it and flash it using the BIOS flashback function. That way my computer is a bit protected from Spectre/Meltdown as well

Unfortunately, it didn't help.

[ImNotThere]

2 hours ago, UltimateByte said:

Well, because of this issue I basically modified my original BIOS using UBU and MCE just to add the latest Intel microcode, that's the only difference compared to the original.

I followed this guide https://www.win-raid.com/t154f16-Tool-Guide-News-quot-UEFI-BIOS-Updater-quot-UBU.html and it actually took just a few minutes to do it and flash it using the BIOS flashback function. That way my computer is a bit protected from Spectre/Meltdown as well

Unfortunately, it didn't help.

Did the CPU info report correct before this bios flash? Also perhaps do a tl:dr, a wall of text puts people off.

[UltimateByte]

I've added the sum up to the begining of my original post.

 

To answer your question: no, it didn't report correct information before the flash (BIOS was already to the latest version... from 2014 on my z87 board) which is why I tried flashing my BIOS with a newer microcode in the first place, without much hope, but I was short of ideas.

[UltimateByte]

Well, just got a replacement 4790K. Guess what? Everything is back in order.