I too would be interested in this, I believe the 8800gs and 9600gso are the same card, and as I can buy one of these for around £45 I'd be very interested in how they operate under osx, I did notice that efistudio has 8800gs listed with 384mb ram which I'm guessing would be the same card.

Just an update, purchased an 8800gs it works fine with efi string, but xbench scores aren't that impressive

Quartz Graphics Test 192.30
Line 212.28 14.13 Klines/sec [50% alpha]
Rectangle 178.92 53.42 Krects/sec [50% alpha]
Circle 297.38 24.24 Kcircles/sec [50% alpha]
Bezier 93.69 2.36 Kbeziers/sec [50% alpha]
Text 600.78 37.58 Kchars/sec
OpenGL Graphics Test 210.87
Spinning Squares 210.87 267.50 frames/sec