The cpu limitations of the high end cards will mean they actually could under perform when matched to older slower kit, the same sort of kit that for example would return excellent fps with a ti 4600 or 9700pro.
I've tried a 6800GT in my #2 machine, a 1.8p4, it was certainly better than the FX5200 thats in it now, but, it scored roughly
12000 marks in 3D Mark 2001 SE! a near identical score to my current PC and my FX5600 - a crap card by anybodys standards :-[ - I tried the same 6800 GT in my #1 machine and it scored 20,000+ out of the box! 8) my point being, my other pc couldnt drive the 6800GT properly but my considerably quicker #1 machine (which I run @ 3.0ghz....) obviously could.
The 6800 GT ran approx 20% slower when I undid my overclock, returning my cpu to 2.6ghz.
To my mind,evidence of the dreaded "cpu limiting"
