I have a Core2Duo E4400, very old, one of the first on the market. I have OC'ed it to by 20% (from 2.0 to 2.4, using the stock OC settings in the BIOS). Anyways, I tend to push it to 100% for a long time, sice I do a lot of rendering. Yes, I know that is OK and my temp stays in the 50-60°C...