Cpu usage 100, gpu 0

[DutchMin]

I've read many forums, tried many things but none seem to work. Hopefully i will find a solution on here. 
So my brothers PC stopped giving video output last week. Troubleshooted it and motherboard had weird brown burnmarks as well as the hard drive. Tried gpu in different system and worked fine. 

To repair the pc i changed the motherboard, hard drive and psu.

 

Now, everything seems to work except two things. First, the big problem. When ingame, every 5 minutes or something, the cpu usage skyrockets too 100% and gpu usage drops to 0-2%. Frame rate drops massively to 2 fps and then after like 10 seconds its back to normal. During this peak the fans turn on really loud on the psu. I've tried a lot but nothing seems to work. 

 

The 2nd problem is that ethernet only picks up 0.1mb/s when plugged in. To bypass that i have bought a little wifi adapter which seems to work but ofc i want to go back to ethernet. 

 

If any help is possible, Would be great.

Thanks already!

[boggy77]

monitor temperatures for cpu and gpu when the weird spikes happen

[airborne spoon]

Sounds like you have a background task that is taking higher priority over the game to the CPU. And when it runs it boggs the system down. check you AV or any other rano background apps you have installed. And you say the PSU fans kick up during the load but not when gaming?

What stuff do you have installed? maybe you're trying to pull too much juice from a small or crappy PSU and its freaking out the system.