[SOLVED] Why is my CPU barely working?

[LifeIsntSimple]

I don't know too much about computers but in the last few months my computer has started to run slower or even crash after playing for a while. When checking task manager my CPU is usually at 80% usage or higher when doing most activities. It also says it's base speed is .79Ghz when it's a 2.8Ghz CPU. I have an Intel core i5-8400, 2.8Ghz 6-core processor, 16 GB of ram, 1 TB 3.5" 7200RPM Internal Hard Drive, a Kingston A400 240GB SSD, and a GeForce GTX 1660 6GB OC Video Card. Any help would be amazing.

 

[Phaaze88]

Temperatures? If it's thermal throttling, you probably need to reapply thermal paste and remount the cooler.

 

[WildCard999]

800mhz is the idle speed so when your not doing anything that is the norm. 2.8ghz is for normal tasks and depending on the application one of the cores may even boost to 4ghz but this depends on the app and the CPU temp. Crashing could be related to temps so monitor with HWmonitor, the CPU should stay under 80C while gaming/heavier loads.
https://www.cpuid.com/softwares/hwmonitor.html

As for the CPU usage having a unknown higher usage could be caused by viruses or malware so you may want to do some full scans with Malwarebytes and a AV of your choosing.