I have seen the AMD Phenom 6.5GHz on a liquid helium and liquid nitrogen cooled system at a temp. of -232 degrees celcius. It had a finishing score 45,474 3DMarks wen all the tests were complete. The Intel i7 965 Extreme has been reported to have held a stable 4.78GHz on a liquid cooled set up and stay strong at 4GHz on nice overclocked setup on the bios. Overclocking just boils down to how much energy, time, and money you are wanting to spend on the system. Honestly, on a server motherboard, you can reach some pretty incredible speeds with very little tweaking to be put into it. My friend's system that i just built for her runs at a steady 3.8 - 4.0GHz ona simple liquid set-up.