OK well I think that my PSU efficiency may be to blame here, I noticed that whenever I start running a 3DM06 run that the PSU fan starts spinning up faster and faster during the graphics tests, then will slow down during the CPU tests, then speed up again, which to my mind is a clear sign that its having to work harder to provide enough juice when the x-fired 4850's are running at max use....

So I'm wondering if when I try to up the VCore etc, and then the cards try to start up whether the PSU is just insufficient to meet the needs..

My PSU is a 2 year old THermaltake Toughpower 750W.

I'm owndering now whether to step up to a 1Kw PSU or just wait it out until the PhenII's come out, which won't be that far off now really...!!!

I probably won't be adding any more gfx cards for the time being, though had thought about getting another 4850 for a HTPC I have, and might have stuck it in this PC to try out Tri-CF, but given the whole PSU thing I'm not sure it would be wise now...!!!