70 deg ??? that is waaay to high. Try to keep it under 60-65 when running prime.
I bought E5200 with stock cooler and removed thermal compound that is preapplied on cooler and put a really fine, thin layer of AS5 paste on CPU.
I am running my E5200 on 3515MHz (10,5x335), 1,26V. Asus P5Q PRO motherboard. It reaches maximum of 58-60 deg when running prime, below 50 in games.
So my suggestion: lower the voltage bacause auto setting overestimates it and apply a thin layer of some good paste between cpu and cooler.
is the fsb & voltage the only 1s that u changed around with? cuz i have the P5Q-E, and i can't seems to overclock it, it wouldn't start up on other settings, did u leave everything else AUTO?!?