Overclocking
According to AMD, Black Edition CPUs are "designed to help you unleash the maximum potential of your system with tunable performance." What this means is that the core multiplier is unlocked, allowing for modification of the CPU speed without changing the FSB or HyperTransport. On a non-black edition CPU, the multiplier is only allowed to be lowered. The standard processors allow for overclocking, however not to the point that a Black edition CPU will.
The Phenom II range of CPUs is the first series of AMD CPUs to eliminate the "Cold Bug," which caused a processor to cease functioning below a certain temperature, preventing the use of "extreme" cooling methods such as dry ice, liquid nitrogen or liquid helium.
In a public demonstration of the Phenom II's overclocking potential at CES 2009 in Las Vegas on 10 January 2009, Sami "Macci" Mäkinen (a record-breaking overclocker) used a Phenom II X4 940 and a DFI LANParty 790FXB-M2RS with a combination of liquid nitrogen and liquid helium cooling to take the processor to a clock rate of 6.5 GHz and succeeded in beating the world record 3DMark 2005 score with a total of 45474.
A group named LimitTeam successfully overclocked AMD’s Deneb 45 nm Phenom II X4 955 processor (Black Edition) on April 30, 2009, and submitted the results for validation to CPU-Z. During the process, the group used the Asus M4A79T Deluxe motherboard, dubbed as the Asus “multidimensional performance platform” featuring support for an AMD 140W CPU and the AMD 790FX/SB750 chipset. As a result, the group reached 7.127 GHz, beating the previous score of 6.7 GHz.
Note that these extreme overclocks involve specialized equipment and are nowhere near what the average consumer could expect using traditional air cooling even with expensive third party cooling fans. For instance, maximum overclocking on a Phenom II X4 955 processor using a heatsink and fan is approximately 4 GHz.
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