Pixel Shader Performance
RADEON X1600 XT copes with simple pixel shaders version 1.1 as well as 2.0 with equal amount of effort, which is quite logical, actually. Since there are only four texturing units, the shader processors waste clock cycles waiting for the data from them. So, the advantages of12 pixel processors start to show off only when the shader gets longer. That is why the newcomer’s performance hardly drops throughout the whole test, unlike the performance of GeForce 6800 and RADEON X1800. The only exception is PS 2.0 Per Pixel shader.
According to a number of tests from the Xbitmark suite, the availability of only 4 TMUs prevents RADEON X1600 XT from showing what it is really capable of. It is especially evident in case of NPR shader (hatch, 8 textures), which name speaks for itself. RADEON X1600 XT shows its best performance in shaders with complex math1ematics and dynamic branching. In the first case RADEON X1600 XT benefits from high working frequency (590MHz against 325MHz by GeForce 6800), and in the second case from Ultra-Threading architecture.
Pixel Shader Tester 1.1 from the 3DMark 2001 SE benchmarking suite doesn’t use a lot of textures, so the four TMUs of our RADEON X1600 XT will hardly be the limiting factor here. As a result, the newcomer is the fastest during pixel shaders 1.1 processing in this particular test. At the same time, just like with Fillrate Tester, it yielded to other testing participants.