2nd CPU Core permanently maxed out

My Amd Athlon 64 x2 3800+'s 2nd core is always at 100% and I'm not sure why, I have looked in task manager and no background processes are hogging memory. This is always leaving my cpu's total usage at 50%. This means doing the most basic of pc tasks, like browsing the web puts my usage to anywhere from 80-100% usage.

Any advice would be greatly appreciated