What do you guys put for the DDR2 ChA/B Reference and Northbridge DDR Reference voltages?

The eqn is 0.5 Vtt x vdimm + Y

As at stock (1.8 - 1.9v vdimm) the resulting voltage would be ~ 0.95v, and I run 2.07v vdimm, I use -30mv for all 3 values, to correct them back to about 1v.

0.5 x 2.07v - 30mv = 1.005v

I don't know how these voltages affect overclocking/stability, so I just corrected them back to around stock, and I have had no issues so far.