On liquid Nitrogen and liquid
Helium
During an AMD-backed overclocking event, a team of overclockers pushed
the Phenom II 955 Black Edition on liquid Nitrogen and liquid
Helium to 7000.4MHz. The score was validated by CPU-Z,
here.
The score was attained on a DFI LP UT790FXB-M3eH
motherboard with digital
PWM. The CPU used was a cherry picked high leakage sample. There were a few TWKR CPUs at the event as well, and some of the participants claim that the difference between TWKR parts and cherry picked 955s isn't too big.
The overclockers also toyed around with 3Dmarks, scoring
50.017 in 3Dmark05 and 38.139 in 3Dmark 06.
More here.