X-bit labs

ATI RADEON X800: R420 Totally Exposed (page 28)

Category: Video

by Tim Tscheblockov , Alexey Stepin , Anton Shilov

[ 05/04/2004 | 06:42 AM ]

Synthetic Benchmarks: Pixel Shaders

The above mentioned McDolenc Fillrate Tester, which we have been using in all our reviews, can also be used for pixel shaders performance tests. Let’s take a look at the results:

As we have expected, the graphs for RADEON X800 XT/PRO are absolutely identical to those of RADEON 9800 XT, except for one thing: the performance. RADEON X800 PRO boasts about 1.5 times higher performance and RADEON X800 XT – twice as high performance than their predecessor.

Despite the higher working frequency, RADEON X800XT outperforms just a little bit GeForce 6800 Ultra in pixel shader 2.0 with 32bit precision, and falls behind the rival when half the precision is applied, which is quite natural, as ATI processors always use 24bit precision during floating-point calculations. In simple pixel shaders 1.1 and 2.0 RADEON X800 XT becomes the leader.

12-pipeline RADEON X800 PRO performs just the way it should compared with the RADEON X800 XT, keeping in mind its lower working frequencies and fewer pipelines. As a result, RADEON X800 PRO manages to outperform GeForce 6800 Ultra only in case of a simple shader version 1.1.

Nothing changes as we disable Z writing.

And when we disable color writes, we see exactly the same situation as during simple texturing with disabled color writes: NVIDIA based graphics cards speed up. NVIDIA GeForce 6800 Ultra manages to get far ahead of its rivals, while GeForce FX 5950 Ultra defeats RADEON 9800 XT.