X-bit labs

S3 Chrome S27 Graphics Processor Review: Worthy Performance for Its Class? (page 7)

Category: Video

by Alexey Stepin , Anton Shilov

[ 12/29/2005 | 12:11 PM ]

Pixel Shader Performance

The strange slowdown with the version 1.4 shaders may be due to some software problems – the shader compiler from S3 seems to need some more polishing-off. Otherwise the new GPU performs well, especially when executing long pixel shaders. The Chrome S27 is faster than its competitors even at running per-pixel-lighting shaders. Well, it can all be explained by one fact – even if the 8 pixel pipelines of the new chip are not as efficient as those of the GeForce 6600 and RADEON X1300, this is well compensated by their sky-high frequency of 700MHz.

Xbitmark isn’t so positive about the GPU from S3. The Chrome S27 successfully handles mathematically complex shaders like Dot Product Bump Mapping + Specular or 27-Pass Fur, but has some difficulty with certain shaders like Wood that uses only one texture. The card is also slow when executing shaders with numerous textures – not surprising, considering it has only four TMUs. The new solution from S3 seems quite competitive overall, but only due to its high frequency. The performance-per-megahertz ratio of its pixel pipelines is obviously lower than that of RADEON X1300 PRO, not to mention GeForce 6600.

Version 1.1 pixel shaders are not a cutting-edge technology anymore, yet the Chrome S27 can execute them quickly enough. It is not any worse than the GeForce 6600 and, in high resolutions, than the RADEON X700.