|"i looked at the cpu fan and theres hardly any thermal paste on it"|
There's not supposed to be much on it but you're not supposed to re-use old paste. I'm assuming that's what you did? Each time the heatsink comes off, the paste is supposed to be completely removed & fresh paste applied.
"im curious my old cpu which is a core 2 duo runs fine at 45-50 degrees but the core 2 quad overheats"
1. improperly applied paste.
2. your Core 2 Duo is probably a 65W CPU, the Quad is a 95W CPU, so that makes the paste application all the more important.