The High Score for AMD overclocking of the Phenom II X3 has been broken again. A Phenom II x3 with all four cores enabled was able to reach 6006.62MHz on a GIGABYTE GA-MA790FX-UD5P.
The overclock was primarily done using multipliers (x26) as the HTT was only bumped up to 231MHz. No word on cooling or the type of voltages needed to get the CPU up to this speed.
RAM used was Corsair DDR2 running a 462MHz (1:2) with timings of 5-5-5-15.
Although there is a CPU-Z validation link going around there are some oddities about it. For one it lists the CPU as an X3 720 while the CPU SPN shows a Phenom II x4 20. It also reports 1CPU - 4 Cores - 4 Threads. This later could just mean the overclocker enabled the other core through the use of the Advanced Clock Calibration feature present in many BIOSes.
Take a look here