FOLDING-Too Hot?

I'm running @ about 55c in core temp @75% load. Is that too hot for 24/7?
Bios is usually 5C lower as a rule.

My server (6400+) running at 3.4 does around 48-50c while folding. I'm sure that those temps (yours and mine) are fine.

You should be fine with that, I know of no program that stresses your core 100%(a real program without the purpose of only stressing your cpu like orthos or coredamage), your chip will be just fine