If that cpu is a G0, and still in the "Conroe", but not "Wolfdale" family, then you should know:
1) default vcore for those E6x00/X6x00/Q6x00 chips was 1.35v.
2) The board has vdroop at load, so 1.275v bios is going to be like 1.21v at full load.

If the Xeon G0 had a vcore default of 1.25v, then that's news to me