hmm... ok heres the deal about the prescott...
w/o the water cooler, u overclock and increase the cpu speed from 2.8ghz to 3.2ghz BUT with the water cooler, it can go up to 3.7ghz... of coz these numbers arent definite. it depends on the type of fans and type of water cooler... hmm...
overclocking is to increase the voltage, thus increasing the frequency of the front side bus (FSB), making the com go faster... though of coz less stable...
but for the prescott it has been tested that even when it is overclocked to 3.7ghz, it is very stable