Hello, I have a similar problem to this guy, who also posted on your forum. Here's his link https://forums.malwarebytes.com/topic/241749-cpu-usage-high-until-i-open-task-manager/.
My name is Joseph and I'm from estonia and would like some help. I built my pc 3-4 weeks ago. It's all fresh except the motherboard, cpu has been used, but the PC is good. I had trial AVAST until it ended. At some point I started noticing that everytime i open my taskmanager it shows 80% or above CPU usage which seems ridiculous, because within seconds it goes down below 10%. My cpu is Intel i7-4790.
It has been used, yes, but it's not broken to be behaving like this. I followed the other guy's article and found some malware or stuff and quarantined it, also i save all the files you asked him to and saved them yesterday, i can do it all again. Before i quarantined the items, i always had 98% cpu usage. One of the items were named "TotalAV", I tried to use it but found out that antivirus is a hoax and a scam. So I dont know, help me please :)