Ok, the chip doesn't run stable at 1.35.
According to Newegg, the X2s are 1.35-1.4 (Varience due to cool & quiet), while the Opterons are 1.3-1.35 (which explains why the tend to OC better, as they're picked to run on lower voltage). I think AMD actualy isn't listed the chip correctly, as odd as that is.