I think that's where it originally came from:

http://my.ocworkbench.com/bbs/showthread.php?%20threadid=69350

AMD Phenom gets killed easily with high vdimm set
--------------------------------------------------------------------------------
According to a reviewer who has been testing Phenom CPUs, he has killed 4 Phenom 9000 series CPU by applying just 2.3-2.5v to the vDIMM setting.

So, beware if you intend to o/c the Phenom, bumping up the voltage to 2.3v can easily kill the memory controller resulting in a dead CPU.