Futuremark 3DMark06 build 1.0.2
The advantage of GeForce 7950 GX2 over GeForce 7900 GT SLI is even more vivid in 3DMark06: the newcomer is 342 points ahead, while the total score is much lower than in 3DMark05. Besides the graphics chip frequency, it is probably the smaller amount of graphics memory by GeForce 7900 GT SLI that matters in this test suite, because 3DMark06 is known to be sensitive to graphics memory subsystem. Despite the 48 pixel processors, Radeon X1900 XTX loses to GeForce 7950 GX2 by the good 1985 points, because the performance in this test suite doesn’t depend only on the pixel processors.
If we consider the results of the SM2.0 tests, the performance difference between GeForce 7900 GT SLI and GeForce 7950 GX2 will be as evident as in the total score chart: the latter is 203 point ahead. Since the overall performance level lies around 4,000 point, this advantage is quite noticeable.
The gap is almost as big in the SM3.0/HDR tests: GeForce 7950 GX2 is 191 point ahead of GeForce 7900 GT SLI. Although GeForce 7950 GX2 and Radeon X1900 XTX feature the same amount of pixel processors, the latter yields the good 849 points to the Nvidia rival. The latter features a lot of functional units such as TMU and ROP, and the performance in this set of tests depends not only on the pixel shader performance.
Since GeForce 7900 GT SLI tandem has only 256MB of graphics memory available to applications, it fails to pass the first SM2.0 graphics test in 1600x1200 with enabled FSAA 4x. in lower resolutions it yields to GeForce 7950 GX2 somewhere between 3% and 10%. For Radeon X1900 XTX the gap makes from 25% to 40% depending on the resolution, and reaches its biggest size in 1024x768, where the performance of GeForce 7950 GX2 is not limited by the slower memory.
The advantage of GeForce 7950 GX2 over GeForce 7900 GT SLI stands out more in SM2.0 graphics test, where it hits 20%. This test is probably less sensitive to fillrate, and besides the new ForceWare driver kicks in and affects the results. Radeon X1900 XTX cannot compete with GeForce 7950 GX2 even despite the little dependence on the fillrate. The solution with pixel processors : TMU : ROP as 3:1:1 cannot really compete with the product featuring 48 pixel processors, the same amount of TMUs and 32 rasterization units.
So, Nvidia GeForce 7950 GX2 outperforms GeForce 7900 GT SLI in individual SM2.0 tests much more than we see in the total score chart. However, we shouldn’t forget that in the former case we used default 3DMark06 settings without full-screen anti-aliasing.