If you open up task manager then right click the process under the processes tab there's an option to 'set affinity' which allows you to select which CPU cores to assign to that process.

There's also an option to 'set priority' which lets you choose what resources to give the process.

Might work, might not.

edit: um, just tried it on the 'system' process - access denied.

I did originally think it was a virus and Sian had done something while I was in worm. Noticed some bits not usually there, htcpassthru, or something similar and another exe. They both seem genuine though and it keeps doing it after stopping those.

Aye, won't work on system. And its only one one core most of the time anyway. I will have to do some investigating when I can be bothered.

I unplugged some USB stuff and all is fine now. Possibly my monitor or the dodgy USB 3.0 ports on the back of the computer.