In a lot of cases it does Will.Dont look like it beats a GTS.
I'm speaking from direct experience too.
The GX2 was so close in performance to the 8800GTS 640mb that i had to go for the GTX to beat it when i upgraded. My GX2 had a swiftech spacer and two zalman fatal1ties fitted which allowed me to overclock as if it was under water.
Excellent cards - ironically, pretty much all the reviews you see use early immature drivers so SLi didn't function properly.
I used some of the later drivers for oblivion and stalker and the GX2 was simply awesome.

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