PC running slow

[JennAndTonic]

Hey,

So the PC I built 4 years ago started slowing down all of a sudden. Everything on my computer is running a few seconds slower than normal, like opening a pdf or checking my email. Any games with higher graphics requirements are also incredibly laggy.

 

Specs:

MSI Z170A gaming m5 mobo

Intel i5-6600k

Zotac GeForce GTX 970

GSkill Ripjaws DDR4-2133 (2x8gb)

Samsung 860 Evo 500gb

Windows 10

 

What I've tried so far:

• Did a scan and didn't get anything back, but reinstalled windows just in case.
• Replaced SSD
• Removed HDD
• Removed GPU and ran with onboard graphics
• Ran memtest86 
• Updated drivers
• Updated BIOS

 

I feel like I've narrowed it down to either the CPU or mobo, is there anything else I can check before I start just buying parts?

[Falcon1986]

When was the last time Windows 10 installed automatic updates? Are any updates in the queue or pending a PC reboot?

[JennAndTonic]

3 hours ago, Falcon1986 said:

When was the last time Windows 10 installed automatic updates? Are any updates in the queue or pending a PC reboot?

Just checked and windows is up to date. 

[Falcon1986]

27 minutes ago, JennAndTonic said:

Just checked and windows is up to date. 

I meant: was an update recently installed? Windows updates are known to cause issues these days.

 

Also open Task Manager and see if anything is causing high CPU usage.

[JennAndTonic]

4 hours ago, Falcon1986 said:

I meant: was an update recently installed? Windows updates are known to cause issues these days.

 

Also open Task Manager and see if anything is causing high CPU usage.

Actually I think I found the problem: my CPU was stuck at 800 MHz; seems like there's an issue where the z170a throttles CPU usage incorrectly. Turned off thermal throttling and things are looking normal again.

 

Thanks for your time!