Just made another attempt. After booting back into windows at stock settings and starting the 3d cube in ATITool (stock clocks) it acted weird (windows flickered etc). Something just isn't working right.

Guess: the ASUS EN8800GT's that have those cheap zalman-lookalike fans on them aren't built on 8800-boards but on 79xx-series boards. I noticed this when I installed the VF1000Cu, I had to use the 7900-holes to fit the VF1000 on it.

So whatever you do, DO NOT get one of those ASUS EN8800GT that have a cheap look-a-like fan on the GPU instead of the stock nvidia full-board one, you'll get a 7900-board with a G92-chip on it.

I guess if I want to do a proper volt-mod I need to check out 7900-voltmodding.