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DeltaChrome As Is
We managed to get our hands on the graphics adapter based on DeltaChrome S8 chip, which is the second fastest VPU from S3G positioned as a direct competitor to mass solutions of the 3D market leaders, namely ATI Technologies and NVIDIA Corporation. As a result we decided to compare it with graphics solutions based on RV350/360 and NV31/36 respectively. If we approach this comparison from a theoretical point of view, DeltaChrome will look not any worse than the solutions from the two largest graphics processor developers.
Moreover, S3G newcomer boasts a number of interesting technologies. The most remarkable one, which we should mention separately is the Chromotion engine. Starting with R300, ATI’s VPUs are known to support real time video streams processing with the help of pixel shaders unit. S3 Graphics engineers have significantly enhanced the idea about involving pixel shaders into video processing. Having implemented this idea in real silicon they called it Chromotion. What can this wonder-technology actually do? In fact, it can do quite a lot of things: the use of pixel shaders allows performing the following with the video streams:
- Per-pixel adaptive deinterlacing;
- 4x4 programmable kernel filter video scaling;
- Real-time post processing;
- Real-time video effects.
All in all, DeltaChrome is very rich in video processing features and boasts the following additional things:
- Hardware MPEG-2/4 acceleration;
- Hardware IDCT and motion compensation support;
- Hardware Windows Media Video acceleration;
- HDTV support (component output);
- 4:4:4 conversion with 10 bit DAC
- 2/3 tap flicker filter with programmable coefficients;
- Vertical over/underscan compensation;
- 2x Oversampling for premium image quality;
- Full range RGB to YUV color space conversion with Hue, Saturation and Contrast adjustment.
S3 has definitely outperformed all its competitors here, although it still failed to become the first in the field of pixel shaders for video streams processing. The leadership here surely belongs to ATI Technologies with its VideoShader, which has hardly been used by the software developers at all (except DiVX Player). We hope that the arrival of the new VPU featuring such wide range of options for video processing will manage to stimulate the developers’ interest and we will finally see the whole bunch of software products using brilliant opportunities offered by VideoShader and Chromotion technologies.
We can’t help mentioning the support of vertex and pixel shaders with the parameters beyond DirectX 9.0 specifications: this is where S3 developers did a really great job. Just take a look at the comparative spec table for NVIDIA, ATI and S3 graphics processors:
ATI RADEON 9800 | S3 DeltaChrome S8 | NVIDIA GeForce FX 5950 | |||
Manufacturing technology | 0.15micron | 0.13 micron | 0.13micron | ||
Number of transistors | 110-115mln | 80mln | 135mln | ||
Chip frequency | 412MHz | 300MHz | 475MHz | ||
Graphics memory controller | 256bit | 128bit DDR SDRAM | 256bit | ||
Graphics memory frequency | 730MHz | 650MHz | 950MHz | ||
Peak memory bus bandwidth | 23.4GB/s | 10.4GB/s | 30.4GB/s | ||
Max graphics memory size | 256MB | 256MB | 256MB | ||
AGP interface | AGP 3.0 4x/8x | AGP 3.0 4x/8x | AGP 3.0 4x/8x | ||
Pixel Pipelines, Pixel Shaders | |||||
Pixel pipelines | 8 | 8 | 4, 8 | ||
Texturing unites per pipeline | 1 | 1 | 2, 0 | ||
Max number of textures during multi-texturing | 8 | 8 | 8 | ||
Texture filtering types | bi-linear | bi-linear | bi-linear | ||
Max anisotropy level | 16 | 16 | 8 | ||
Pixel shaders version | v.2.0 (f-buffer, v2.0+) | v2.0+ | v.2.0+ | ||
Branching, subroutines and loops | none | n/a | none | ||
Max number of textures per shader | 16 | 16 | 16 | ||
Max number of texture instructions | 32 | n/a | 1024 | ||
Max number of arithmetic instructions | 64 (+64) | n/a | 1024 | ||
Max number of instructions per shader | 96 (+64) | n/a | 1024 | ||
Registers | 2 color registers, 4 resulting color registers, | n/a | 2 color registers, 4 resulting color registers, | ||
Data representation formats | Fixed point, | Fixed point, | Fixed point, | ||
Internal Pixel Shader Pipeline Precision | 96bit pixel precision/24bit floating point precision | 96bit pixel precision/24bit floating point precision | 128bit pixel precision/32bit floating point precision, 16bit floating point precision | ||
Vertex pipelines, vertex shaders | |||||
Vertex pipelines | 4 | 4 | 3 | ||
Vertex shaders version | v.2.0 | v.2.0+ | v.2.0+ | ||
Branching, subroutines and loops | Static | Dynamic, 16x16 maximum loops | Dynamic | ||
Max number of instructions per shader | 256 | n/a | 256 | ||
Max number of instructions with loops extension | 65536 | 65536 | 65536 | ||
Registers | 16 input registers, 8 output registers for texture coordinates, | 16 input registers, | 16 input registers, 8 output registers for texture coordinates, | ||
Data representation formats | 32bit floating-point |
| 32bit floating-point | ||
Full-Scene Anti-Aliasing | |||||
FSAA methods | Rotated grid multi-sampling | Supersampling, Multisampling | Supersampling, | ||
Number of samples | 2, 4, 6 | 2 | 2 (OGSS, OGMS), | ||
Technologies aimed at higher memory bandwidth efficiency | |||||
Hidden Surfaces Removal (HSR) | Yes | Yes | Yes | ||
Frame-buffer compression | Yes | n/a | Yes | ||
Z-buffer compression | Yes | n/a | Yes | ||
Other techniques | Yes | Yes | Yes | ||
As you see, the abilities of DeltaChrome solution in terms of shader processing is far beyond the DirectX 9.0 minimal requirements. Will the game developers really take advantage of it? It is hard to answer this question, actually. But if this is ever destined to happen we will have to wait for quite a long time, maybe until these features become a widely spread standard.
Besides that, DeltaChrome features bi-directional color and Z buffers, supports hardware GDI+ acceleration, can lay up to 16 textures per single pass and perform 2x supersampling and up to 16x anisotropic filtering. Unfortunately, the current driver version doesn’t support multi-sampling, which the company also claims as one of the features.
Theoretically, DeltaChrome looks like a very successful solution: the chip boasts a lot of interesting features and strikes as pretty competitive. However, it is high time we shifted from beautiful and promising but “theoretical” tables to the real graphics accelerator and find out what the new S3 baby is actually capable of.
