Rebellion88

Yes the main concern is the heat build up, although each processor has its own limit too much and it fry for obvious reasons. Pushing the processor beyond its capabilities can shorten the lifetime of the component. Good cooling will always aid overclocking, but for the majority of processors overclocking over 400mhz is when you really are pushing it IMO. Although i have seen AMD Athlon XP's 2600 barton cores OC'ed to match a 3200 if not a slight bit faster. Going higher will also require to increase the volts going through making sure its getting enough power to juice the performance.