These tests were run on a system with an Intel Core 2 Extreme QX6800 processor, Asus P5W DH motherboard, 2x 1GB PC2-6400 memory with 5-5-5-12 timings and a Western Digital Raptor HDD.
3DMark 06:
3DMark06The second test was a Crysis demo with the details on high:
ATI HD 2900 XT 512MB: 10356
NVIDIA GeForce 8800 GTS: 10951
3DMark06 - PS 3.0
ATI HD 2900 XT 512MB: 4712
NVIDIA GeForce 8800 GTS: 4998
3DMark06 - PS 2.0
ATI HD 2900 XT 512MB: 4806
NVIDIA GeForce 8800 GTS: 4876
1024 x 768So to wrap it up, in 3DMark06 the GeForce scores higher but in the upcoming DirectX 10 game Crysis the Radeon HD 2900 takes the upperhand.
ATI HD 2900 XT 512MB: 81.4
NVIDIA GeForce 8800 GTS: 72.5
1024 x 768 4x AA + 16x AF
ATI HD 2900 XT 512MB: 74.7
NVIDIA GeForce 8800 GTS: 67.2
1280 x 1024
ATI HD 2900 XT 512MB: 76
NVIDIA GeForce 8800 GTS: 68.1
1280 x 1024 4x AA + 16x AF
ATI HD 2900 XT 512MB: 66.8
NVIDIA GeForce 8800 GTS: 61.9
1620 x 1200
ATI HD 2900 XT 512MB: 65.3
NVIDIA GeForce 8800 GTS: 62.5
1600 x 1200 4x AA + 16x AF
ATI HD 2900 XT 512MB: 52.8
NVIDIA GeForce 8800 GTS: 50.2
However, keep in mind that these results don't come from a trusted source. It's possible that they've been made up because the R600 isn't on the market yet and a Crysis demo neither. So take these results with a grain of salt.