Recently I bought an Alpha6035 cooler for my 366MHz PPGA Celeron. It didn't run stable before (@550MHz), especially not below 2.1V. With the Alpha on it, I can 100% stable at a voltage of 1.85V (1.9V with case closed). But if I want to run it at 578MHz, I can't get it stable, not at any voltage up to 2.3V. It is not heat, cause my Alpha fan runs at 7V (I think @12V it is MUCH to noisy!) when I run it at 550MHz with 1.9V and it is not stable (@578) when I run the fan at it's default 12V. The heatsink does not get warm, the thermal paste is also aplied properly. Has my CPU reached it's physical limits? If that is the case, I will stop putting any more effort in trying to get it higher.

Sorry if this post is a bit confusing, but I hope anyone can help me,