The Radeon X1900 XTX has to leave the top place in 3DMark06 to Nvidia’s new graphics card which has scored 142 points more. Not much of a difference, but the GeForce 7900 GTX is the leader nevertheless. Note also that the performance has grown much relative to the GeForce 7800 GTX 512 – 580 points is quite a lot for 3DMark06. This is expectable since 3DMark06 makes wide use of shader-based visual effects.
There’s a smaller difference between the multi-GPU configurations on Radeon X1900 XT and GeForce 7900 GTX than between the respective single cards and amounts to 31 points only. So, we should regard these two top-end graphics solutions from Nvidia and ATI as equivalent in 3DMark06.
The Radeon X1900 architecture cannot show its very best in the SM2.0 tests because they do not use version 3.0 shaders. Moreover, the first test is a very large scene and seems to be the reason why the GeForce 7900 GTX has a higher overall score than the Radeon X1900 XTX. We’ll check this supposition shortly.
The GeForce 7900 GTX finds it more difficult to crunch through the SM3.0/HDR tests. It is slower than the Radeon X1900 XTX with its 48 pixel processors and Fetch4 technology.
The GeForce 7900 graphics processor cannot do full-screen antialiasing and work with HDR all the same time, so we publish the SM2.0 tests results for the 4x FSAA + 16x AF mode only. The performance is too low at higher levels of antialiasing, which is no good for the measurement accuracy.
As we had suspected, the GeForce 7900 GTX came out on top in the first SM2.0 test, leaving the Radeon X1900 XTX behind in two out of three display resolutions. The new card just wanted a little more of memory subsystem performance to win the resolution of 1600x1200, too. Although the memory frequency of the Radeon X1900 XTX is somewhat lower, it is governed by a more efficiency ring-bus controller whereas the GeForce 7900 GTX uses a traditional controller.
We see the same as we compare the Radeon X1900 XT CrossFire with the GeForce 7900 GTX SLI. The former overtakes the Nvidia platform by a narrow margin in 1600x1200 resolution only. In the lower resolutions, the ATI platform is about 10% slower.
The second SM2.0 test is less sensitive to the texturing speed than the first one, so there’s not much use from the 24 TMUs here. This is why the GeForce 7900 GTX is only equal to the Radeon X1900 XTX in 1024x768 and falls behind in higher resolutions, by up to 15%. The same goes for the struggle between the two multi-GPU platforms, too.
So, our supposition about the overall scores of the SM2.0 tests has been proved by the results of the separate tests. The GeForce 7900 GTX really owes much of its overall advantage to the first, large-scale test.