Foxy,
yes, it's set to use all available processing power by default.
I haven't done this lately, and I'm at work so this could be wrong, but if you right click on the folding@home icon in your startup tray, click on settings. There is a tab labeled advanced. Under this there is a slider bar that can be changed. Just try lowering it to 50%. That should solve you high CPU temp.
Just a question, but do you have decent airflow goingthrough your case? If you have a jumbled mess of wires inside of your case, like my case at home is, try cleaning it up. That might solve you temperature problem. I fixed it by taking the side off of my case.