Just spotted this bit of news posted over at Slashdot.

The 6GHz barrier has been broken by two guys, a little LN2 (liquid nitrogen for those not as chemistry inclined), and an Intel Pentium 4 (Prescott) 3.60GHz. Check out some icing and some proof of speed. Better yet take a look at how fast it calculates pi. Also be sure to check out the original announcement.