About 3 years ago I had my P3 550E@825 running under 50º at 100% work load.
Can you check if it is a 500E or a 500 ?
Don't forget that
if you got a P3 500E, that is quite a good overclocker.
Could you improve ventilation on the case ?
That P3 should hit 665 without much trouble if it is...
If it is a Katmai, one of the old ones, maybe you could try 560... Don't even bother to try more if you don't have good cooling.
P3 500 average
612 on overclocker.com and the 500E averages
744
Let me know more info and i'll help ya out more... but with those temps, it looks like its a no go
