Underclocking Games

[Ian C]

There's no dust in the case or fans. The temp increase occurred just after the last major Windows 10 update and it also changed the settings in the AI Suite II (AMD's fan app).
As far as I can tell, I put it down to the update.

[Yskonyn]

Ian, I found this on the Microsoft KB while digging a bit for you because I find the issue weirdly interesting. I am pretty sure it's due to some software process keeping your CPU busy.

I have found a few claims of related issues and fixes. YMMV of course but at least its worth a try.
First one:

"This should resolve your issue:
Reset Windows Defender Firewall:
Settings -> Update and Security -> Windows Defender -> Open Windows Defender Security Center -> Firewall and Network Protection -> Restore Firewall default settings > Click the button to restore the defaults
Or
Use the Windows Firewall repair tool:
https://support.microsoft.com/en-us/help/17613/automatically-diagnose-and-fix-problems-with-windows-firewall"

Second, but more advanced:

https://www.drivethelife.com/windows-10/fix-high-cpu-usage-windows-10-fall-creators-update.html

Let me know if it worked.

[Nefaro]

If its an older CPU its likely the cooling paste between the chip and fan needs replacing. Easy to do. Or
You could invest in an off the shelf closed liquid system.

Having been in the business of computer repair for a number of years, I've witnessed this fairly often on computers which have been runnying steadily for years.  Especially those that tend to be left on and idling for days.  This was the cause of most customers' overheating issues, discovered after they'd bring them in for repair due to regularly crashing & self-restarts.

The steady heat eventually bakes the thermal paste, slowly lowering it's ability to efficiently transfer heat to the heat sink in order to dissipate it faster. 

After my desktop PCs hit ~5 years of steady use, I clean off the old thermal paste and put a new application on.  Can always tell the old application has degraded when I do.  I'll do it a bit earlier if I happen to have the case open, doing some other fixing or upgrading before then, but 5 years is a good time to catch it before it gets too bad.  Maybe earlier if it's getting a lot of usage.

I'm sure Yassy already knew this stuff.  My commentary was meant for others who may not know.

[Ian C]

Ian, I found this on the Microsoft KB while digging a bit for you because I find the issue weirdly interesting. I am pretty sure it's due to some software process keeping your CPU busy.

I have found a few claims of related issues and fixes. YMMV of course but at least its worth a try.
First one:

"This should resolve your issue:
Reset Windows Defender Firewall:
Settings -> Update and Security -> Windows Defender -> Open Windows Defender Security Center -> Firewall and Network Protection -> Restore Firewall default settings > Click the button to restore the defaults
Or
Use the Windows Firewall repair tool:
https://support.microsoft.com/en-us/help/17613/automatically-diagnose-and-fix-problems-with-windows-firewall"

Second, but more advanced:

https://www.drivethelife.com/windows-10/fix-high-cpu-usage-windows-10-fall-creators-update.html

Let me know if it worked.

Thank you for your help Yskonyn. It is very gracious of you to look into this issue.

I've traced the issue to multiple instances of Acrobat Reader not closing after opening it. I open it several times during the day - and each instance continues running in the system tray (5 or more). When I manually end the tasks, my CPU returns to normal. The problem is they were running while I was playing games. Looking into it now...