[SOLVED] URGENT HELP!! i7 8700k (6C12T) suddenly missing a thread (6 cores 11 threads now)

thtran6

Upstanding
Oct 2, 2018
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Hey everyone,

My spec:
-MSI Z390gaming pro carbon ac
-i7 8700k @5.3 ghz 1.4 vcore delidded
-msi gaming xtrio 2080 ti
-4x8gb gskill trident Z royal 3600 mhz cl 17
-samsung 970 evo plus 500gb
-evga g2 850w power supply
-corsairs h150i (360mm with 6x120mm noctua push/pull) with thermal grizzly kryonaut

So MSI released a new BIOS recently and I decided to flash my BIOS yesterday. I've flashed BIOS numerous times and know what I'm doing.
Everything was working perfectly fine after the BIOS update.

However, as I was scrolling through Task Manager, I noticed there was only 11 threads showing up.
I checked CPU-Z and it shows 6 CORES 11 THREADS !
I checked HWmonitor and it shows all 6 cores running @5.3 ghz, but only 11 THREADS too
I did msconfig --> boot --> Advanced Option and saw only 1 to 11 in the drop down list.

I have NEVER seen anything like this before! 8700k with 6 cores but only 11 threads?
I am 100% sure that my 8700k with 6 CORES 12 THREADS was showing up correctly in cpu-Z and hwmonitor and task manager just a few days before!

Did the BIOS update somehow screwed me up?
Is this just a problem with the system misreading the # of CPU threads?
OR, is a thread on my CPU actually BROKEN/DEAD???


I am very lost now. PLEASE help me. I appreciate any input!
Thank you very much guys!!!
 
Last edited:
Try to eliminate overclocking and see.
If it dose not help go to BIOS setting and see the cores setting, it may be changed. and restore the default setting.

i did get rid of the overclock and reset everything BIOS to default values.
Also I have made sure that hyper threading is ON.

I think in the BIOS it is still recognizing the 6 cores just fine. But idk where to obtain information on the 12 threads?.

Now, back to window, after all that adjustment, yes cpuZ and hwmonitor still shows 6 cores and 11 threads @@
 
I'd like to see some screenshots.

View: https://imgur.com/a/28N13gJ


Please see the above link for 4 screenshots.
1st screenshot: CPU-Z showing 6 cores 11 threads (instead of 12 threads)
2nd screenshot: HWmonitor showing 10 thread (CPU#1 to CPU#10). Before, it was showing CPU#1 to CPU#12
3rd screenshot: Task Manager showing 11 threads
4th screenshot: msconfig --> boot --> Advanced Option only display up to 11 number of processors (was 12 before)

I am an experienced pc builder and have built more than 20 pc but this is the first time I've seen this kind of stuff @@
 
Have you tried linux or something? It's possible that certain key registry entries are messed up, if not then it has to be the hardware. I'd try a few OS before going to the hardware part, use them live ISO.
 
Have you reverted to the previous bios to see if problem goes away? Have you tried optimized defaults?

This is a real head scratcher. With my 20+ builds i have never seen a thread just go missing.
Don't revert (just yet) but check out the motherboard's forum to see if the new bios is in deed having problems.

Your bios could have individual HT settings for each core so you will have to search through your whole bios thoroughly to see if that's the problem,although using the optimized defaults should enable all cores and threads and you said you already tried that.
 
UPDATE: (spoiler - problem solved)

Here are the things that I have tried and DID NOT work::
(1) reinstalling Window
(2) downgrading BIOS version, running at default BIOS setting
(3) removing all overclocks
(4) running at stock frequency for ram and cpu
(5) disabling Hyper Threading and then re-enable it again
(6) reinstalling latest version of CPUZ, HWmonitor, HWinfo

I went into msconfig --> Boot --> Advanced Option, and look at the drop down list and it's still the same, the list only goes from 1 to 11 number of processors. I tried scrolling down to see if the 12 is at the bottom but no... 11 is still DEFINITELY the last one.

So what I did was I unchecked the box with "Number of Processors", rebooting my pc, and go into msconfig --> Boot --> Advanced Option, and checked the box again...... and guess what, the magic number 12 appears!

I selected 12 there, rebooted one more time, and double-checked Task Manager, CPU-Z, HWmonitor, HWinfo...... and YES!!, all 12 threads are showing up correctly now.

I know this is quite a simple fix but really what in the world caused this problem in the first place????? I still have no idea....

And yes, shoutout to SkynetRising for the tip!!
And thank you everybody who commented to help on this post. Truly appreciate every comment.

I hope this helps somebody else in the future, because prior to this, this problem never exists in the database of Google and I could not find anything related to this problem at all!
 
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