Yeah, that CPU usage for just torrenting is way too high. I say it is a virus since you already been checked the inside to make sure you don’t have a dead fan.
There is 1 last anti-virus scanner I use which I have not suggested yet, Kaspersky Anti-Virus / Kaspersky Internet Security. I am not sure which anti-virus scanner you have running in the background or if you have one at all but IMO Kaspersky is the best one. It’s the one I always have running on my desktop and laptop. I just didn’t suggest it before since you have to pay for it. But I found a trial link from the company that will allow you to run a full version of Kaspersky Internet Security for 30 days for free. Uninstall whatever anti-virus program you have running in the background before you install Kaspersky. After Kaspersky is installed make sure you run a Full/Thorough computer scan.
btw, there is at least 1 virus out there that masks itself under svchost.exe. Last time I dealt with that virus was about 6 years ago. Not sure if Kaspersky removed it at the time or if I had to reformat the PC at my job that had it.
ALTERNATIVELY, Kaspersky offer a free “Virus Removal Tool” program. This one I have never used but heard many good things about it. You can try this first, if it does not work then go the full version trial linked above.