X-bit labs

S3 GammaChromeS18 Graphics Processor Preview (page 6)

Category: Video

by Anton Shilov , Anna Filatova

[ 03/14/2005 | 07:34 AM ]

Vertex and Pixel Processors

Similar to its predecessor, S3G GammaChrome graphics processor supports extended DirectX 9.0 specifications and can process Pixel and Vertex Shaders 2.0+ with 24bit and 32bit precision respectively.

According to S3 Graphics, the same number of vertex and pixel processors (4 of each) guarantees better-balanced gaming performance. However, we wouldn’t take this statement for granted and will be checking it in real gaming applications before making any final conclusions. We are already running all necessary benchmarks and soon will offer you a detailed report of how balanced the gaming performance of the new GammaChrome actually is.

The list of additional new features acquired by the GammaChrome pixel and vertex processors is impressively long:

• Up to 16 concurrent texture map references per pass
• Shadow Volume acceleration with two-sided stencil
• Non power of 2 textures
• High accuracy floating point render targets for cinematic quality image rendering
• High quality advanced 16X anisotropic filtering
• High quality rotated grid full screen anti-aliasing with 4X supersampling up to 1600x1200
• Volume and cube maps for photo-realistic reflections
• Programmable per pixel gamma correction
• High Performance Fast Tri-Linear filtering
• Full floating point precision ALU for single clock execution per pipeline for PS 2.0 operations
• Programmable cache for engine speed and efficiency
• Unified superwide pipeline for seamless 2D/3D/Video context switching
• Optimized advanced shading dependency read pipelines
• Programmable render target blending (PS2.0)
• Programmable depth shader (PS 2.0)
• Zero latency – ultra fast zero cycle clear
• Optimized Z buffer write and read
• Triangle mask optimization
• Fast Clear technology

In the meanwhile S3 Graphics doesn’t reveal a lot of details about the innovations introduced in their GammaChrome S18 and S19 family. However, I suppose that the most serious changes have been made to the data caching system. We do not know exactly yet if the new S18 now have more execution units (although we are pretty much sure that it does), however, S3G claims that they eliminated a number of “issues” they used to have since the times of DeltaChrome. They also claim that they will make a number of additional improvements and optimizations to their upcoming S19 model, which will have 8 pixel pipelines.

The only thing that is evident so far is that the company is using 0.13micron manufacturing technology, which permitted to increase the working frequency of the chip. Higher core clock together with some architectural optimizations (supposedly higher number of ALUs per pipeline) allowed the four-pipeline GammaChrome S18 PRO to compete with ATI RADEON X600 PRO. As we all remember, DeltaChrome S8 with 8 pixel pipelines could hardly retain the parity with RADEON 9600 PRO featuring only 4 pixel pipelines.