going by the stage name Luca has managed to overclock AMD's new six-core T1090 Black Edition to a whopping 6.29GHz.
The 1090T is stock clocked at 3.2GHz and LN2 cooling was used to keep
the six cores from burning a hole in the carpet. Interestingly, Luca
used an Arsrock 890GX board and 1GB of Kingston memory to pull off this impressive feat.
You can check out the CPU-Z validation here