Bootcamp on MBP - Processor stuck at base frequency

[mrciave]

New to the forum, so hello to everybody.

After months talking with Apple support and basically getting told to update the Bootcamp drivers, I'm still stuck with my problem.

Windows 10 on Bootcamp, 2018 MBP with i9-8950HK processor. High Performance plan running on power supply. When I run heavy processor calculations, processor throttles from the 4.5GHz when not doing anything, down to below the base frequency of 2.90GHz (sometimes even 2.2GHz) depending on temperature.

When the load gets lighter, going back towards the 4.5GHz.

But sometimes, processor gets stuck at the base frequency (2.90GHz), and then does not move anymore from there, independently from the load.

This makes it much slower for computation.

When asking again full load (parallel computation on all cores), I'm able to recover it and then turbo works normally again.

Anyone have any idea how to fix it?

Thanks a lot!

 

[mrciave]

No one?

 

[Chocomonsters]

I have same 2018 MBP 15 with i9. I too am experiencing a random stuck processor at the base frequency. It will fully boost up and run with expected thermal throttling on and off. But when heavy CPU load is finished, it will return to base or lower as expected. However, if new heavy CPU load is started, it fails to resume boosting even after it has cooled off. Only way to reset for me is to reboot.

 

[mrciave]

OK so you're in a worse situation than mine. Did you ask help from Apple or Microsoft?

Honestly, I'd like to understand if it's faulty HW or just a SW bug. But so far Apple has been useless...

 

[Chocomonsters]

OK so you're in a worse situation than mine. Did you ask help from Apple or Microsoft?

Honestly, I'd like to understand if it's faulty HW or just a SW bug. But so far Apple has been useless...

Obviously this does not happen under MacOS and not likely represents faulty HW. I assume it is related to T2 security chip with limited access to CPU.

AFAIK this is Intel CPU level issues, not MS Windows 10 issue. You can download and run Intel Extreme Tuning Utility to monitor. You will notice thermal throttling kicking in regularly during heavy CPU utilization, but rarely ever see power limit throttling or current limit throttling. With thermal throttling, it will return back back to max frequency. When it is stuck at 2.9 base frequency, it is not in response to thermal throttling. It is just random.

 

[angrybob100]

Same issue - Either have to exit throttlestop to reset the FID/VID or reboot.

Seems to trigger fairly randomly, when I am doing nothing for instance. Othertimes I can play a complex sim for ages.

Intel Extreme Tuning utility seems to suggest it is 'power limit throttling', but when tripped, it just gets stuck.

Pretty annoying.

 

[angrybob100]

Even sometimes it is not power limit throttling - It shows and no throttling.

Not sure whether we can see the same in MacOS, so don't know if it occurs there. Any good utils?

 

[mrciave]

It seems something has changed lately in the throttling style under Win10 in BootCamp.

While before throttling was progressive, transitioning smoothly from the 4.50GHz down to 2.90 and below (and sometimes getting stuck at 2.89), now throttling is more "digital", jumping from 4.3-4.4 to 0.80 and back. If I compute the average, performance is good, but when processor jumps to 0.80Hz, any gaming or real time simulation can't keep up in real time.

So, one problem solved (does not get stuck anymore at 2.89), but another one as a result of it.

And helpless same as the previous time...

 

[mrciave]

Forgot to say, when it jumps to 800MHz it’s the usual PROCHOT flag.

 

[aliensporebomb]

I've got something similar happening to my Mojave system (4ghz i7 iMac with 32 gigs of ram).
I'd posted that I thought something similar was happening under MacOS but I couldn't prove it.

I'd run geekbench and my ratings would be half to three quarters of what they were a few months ago.
It just seemed noticeably slower from reboot to reboot.
And I hadn't updated geekbench to the latest version.

I posted some messages under the MacOS threads but never really got conclusive proof but it seemed
related to a recent Mojave update (not 10.16 but one or two before that).

MacOS doesn't seem to have similar system clock tools such as CPU-Z or HWMonitor.

Under Windows 10 the system sticks at 0.78 ghz (or around 799 mhz) no matter what I do.
This sticks from reboot to reboot.

The Intel processor diagnostic tool indicates:
Expected frequency 4.0 ghz
Measured frequency 3.9895 ghz

But Task manager, CPU-Z, HWMonitor, etc all show this stuck at 798.10 Mhz.

I'm not running throttlestop - should I be?
System power set to high performance, don't sleep the display or HDD.

I am running Macs Fan Control 1.4.12 that controls temp based on GPU diode.
That's the latest version of that utility.

Any ideas? I've never seen this before but my entire machine seems very noticeably slower but the only place I have raw data in numbers is on the windows side.

 

[aliensporebomb]

Update - shut machine down for an hour and booted into windows again. Ran only task manager, MacsFan and CPU-Z and the clock speed dropped precipitously from 4+ ghz to 800 mhz within 13 minutes and stayed at 800 mhz at that point.

 

[aliensporebomb]

Update - fixed - freaking stupid dust in the vents, much more than seemed possible. Actually used a vacuum in combination with compressed air can. Machine works like new now.