I read a post by houserate (sp) who suggested that we maybe using way to much voltage when overclocking. I did some subjective testing, here are the results...
X1900xtx
P5WD2-E Prem
660 3.6 OC to 4.2
X-Fi Platnium
PC Power and Cooling 510 Express/SLI
*120MM Fan on Vregs and Mosfets (with copper heatsink...results will very)
ATI TOOL OC to 711/810 that's only 11MHz on core and 10 MHZ Mem higher then CCC Overdrive
During the initial OC at 1.40/2.160/2.160 the Vreg reached as high as 58C.
During the recent OC @ 1.35/2.130/2.130 the Vreg reached as high as 55C.
It appears that the lower voltage increased HDR/SM 3.0 scores. This is subjective opinion.
Ok here is what happens when I reduce:
VGPU from 1.40 to 1.35
MVDDC/MVDDQ from 2.160 to 2.130
Score on 3DMARK06 5791 (again, subjective however, this is with a lower voltage regardless if its only a 3 mark gain from 5789). This would sugges that we are playing a juggling act with heat and voltage not with the core and mem but with the mosfets and vregs!!! If you water cool you need some serious cooling for those vregs/mosfets! If you do it's possible to see an nice bump using the same core/mem OC's!
ATI Vreg water cooler. <--This is the only water cooled solution I that was given to me that I know of to date. Any suggestions is appreacited.