Managed to get it installed with no hassles in under 5 minutes which was a pleasent surprise. I've not fully stress-tested it yet, but it seems happy enough with my 300w PSU.
Performance wise could be a bit of a downgrade it seems - I'm gonna have to push it a bit harder before I'm sure, but initial results put it as being slower than my Radeon 9800:
3D Mark 2005
Radeon 9800 = 2463
GeForce 6800 = 2072
3D Mark 2006
GeForce 6800 = 1161
Radeon 9800 = 636
I'm pretty sure that the higher '06 score is simply due to the hardware supporting the SM3/HDR tests thus picking up points where the Radeon didn't.
Although, performance doesn't seem that much worse - and I'm happy enough to trade a bit of performance for the SM3 goodness [smile]