of course much depends on processor speed ... overclocking is a science by its own ... read through various overclcocking sites and you will find suddenly you need to care about memory types and voltages, heat dissipation, BIOS settings, bus frequencies, ect.
in a nutshell: overclocking is nothing supported by VSL as hardware in general is not our business. we gladly provide information about working configurations and some insight where possible though.
in other words: to transport a ton of bricks we recommend to use a truck. maybe you could do that with your cadillac too, but do this at your own risk.
christian
and remember: only a CRAY can run an endless loop in just three seconds.