A brief overview
Before NVIDIA and ATI's fairly recent dominance in the discrete graphics card market and related diversification into motherboard core-logic designs, S3 Graphics was a major player in its own right. Recently, though, the company has focussed on releasing a number of new SKUs for the low-end of the market. UniChrome (integrated), DeltaChrome and the PCI-Express-based GammaChrome being the obvious examples, and whilst, in terms of specification, each iteration has often matched NVIDIA and ATI's low-to-midrange GPUs of that time, a lack of partner support and, it has to be mentioned, relatively poor software drivers and game incompatibility have kept its products from the limelight.S3G's back with its ChromeS20-series of GPUs which currently comprise of the PCIe-based ChromeS25 and ChromeS27, both of which can be configured for either desktop or notebook usage.
3D thoughts
Let's first take a look at the GPUs' specifications with respect to 3D attributes:
| Card | S3G ChromeS27 | S3G ChromeS25 | ATI RADEON X1300 PRO | GeForce 6600/GT |
| Shader Model | 2.0+ | 2.0+ | 3.0 | 3.0 | Native interface | PCI-Express | PCI-Express | PCI-Express | PCI-Express | Onboard memory | Up to 256MB | Up to 256MB | 256MB | Up to 256MB | Memory type | GDDR1, GDDR2, GDDR3 | GDDR1, GDDR2, GDDR3 | GDDR3 (initially) | GDDR1, GDDR2, GDDR3 | Core speed | 700MHz | 600MHz+ | 600MHz | 500MHz | Manufacturing process | 90nm | 90nm | 90nm | 110nm | Transistors | 50-70m | 50-70m | 105m | 146m | Pixel shaders | 8 | 8 | 4 | 8 | Vertex shaders | 4 | 4 | 2 | 3 | Fillrate (multi-texturing) | 5.6GTexels/s | 4.8G+Texels/s | 2.4GTexels/s | 4.02GTexels/s | Memory interface | 128-bit | 128-bit/64-bit | 128-bit | 128-bit | Memory speed | 1400MHz | 1400MHz | 800MHz | 1000MHz | Memory bandwidth (max) | Up to 22.4GB/s | Up to 22.4GB/s | 12.8GB/s | 16GB/s | AntiAliasing and Anisotropic Filtering | Unknown | Unknown | 6X AA, 16X AF) | 8XS AA, 16X AF | Multi-GPU technology | MultiChrome - details unknown | MultiChrome - details unknown | CrossFire | SLI | Expected price | <£85? | <£70? | £100 | £80 |
We've paired the two main S3G ChromeS20-based boards up against the likely competition from ATI and NVIDIA. Taking the juiciest bits out of the table above, the ChromeS20 series, headed by the ChromeS27, are, surprisingly, manufactured on an advanced, low-k 90nm process by Fujitsu and are compliant with upcoming ROHS legislation (Restriction Of the use of certain Hazardous Substances), meaning they're lead-free and get the thumbs up from the environmental brigade. Both S3G GPUs use native PCI-Express interfaces and have 4 vertex and 8 pixel shaders, although, without direct knowledge of just how powerful and efficient they are, comparisons between them and the established hierarchy is currently just conjecture.
The ChromeS20 line supports shader model 2.0(+) but fall short with respect to SM 3.0 for both pixel and vertex shaders, so no dynamic branching, geometry instancing, or true high-dynamic range lighting, for example. S3G maintains that its next iteration of GPUs will feature SM 4.0 support, as and when that arrives. It's not completely clear just how far beyond SM 2.0 spec. the ChromeS20 series hardware currently stands at, though.
On the plus side, the use of a 90nm manufacturing process has enabled S3G/Fujitsu to crank up core speeds to 700MHz on the ChromeS27 and 600MHz+ on the 'S25. Right now, that makes for the fastest core speeds around, although the correlation between core speed and overall performance is a tenuous one and influenced by many other factors. Cards from the ChromeS20 range can be paired with 3 types of video-card memory, right up to some tasty GDDR3 RAM operating at an effective 1400MHz which, when run through a 128-bit interface, offers around 22.4GB/s of bandwidth before any GPU-induced efficiency is taken into account.
It can be difficult to correctly compare transistor counts between competing products due to the fact that each manufacturer may include certain transistors that others do not. S3G claims a transistor count of between 50-70m, which, as you can see, is considerably lower than both NVIDIA and ATI's competing products. What this and due appreciation of the 90nm manufacturing process gives rise to and not shown on the above graph, is the power requirement of the ChromeS20 range. S3's literature contends that the range-topping ChromeS27, when assessed from a complete card viewpoint, uses between 17-30W, which is impressive for a midrange 3D accelerator. The ChromeS25 is reckoned to need between 15-30W, and a 64-bit (memory interface) version of the same GPU between 10-20W. We expect to see a number of ChromeS2xs use passive heatsinks in desktop models, and we'll no doubt see the entire line duplicated for notebook usage. In the GPU performance-per-watt category, then, S3G should do well.
Whilst we've not formally tested any ChromeS20 SKU ourselves, S3G reckons that the ChromeS27, when evaluated in 3DMark05, should benchmark in the 3,500-mark range. The ChromeS25, S3G contends, will score around 2,500 marks, and the 64-bit version around 1,500 marks. To put this into some kind of comparative context, a default-clocked GeForce 6600 GT benchmarks in at around 3,700 marks. Benchmarking results from a synthetic benchmark give us some idea of GPU strengths, but we'll have to wait and see how the ChromeS20 range performs with a batch of modern games. If recent history is anything to go by, S3G's hardware has stacked up reasonably well against the established competition, but its drivers have left a lot to be desired, with game incompatibility and, sometimes, erroneous rendering far too worrisome to be ignored. S3G states that it has around 300 people working on its software side; we fervently hope that they can do a good a job as ATI or NVIDIA's engineers. The best hardware in the world doesn't count for much if compromised by substandard drivers. Only time and hands-on testing will reveal if S3G's drivers and rendering is up to scratch. The outlook does look good, however, as even 2 months ago S3G was showcasing excellent compatibility with over 40 modern games that you may well have heard of; the list now stretches to around 200, we believe.
The budget ChromeS25 also supports ATI HyperMemory- and NVIDIA TurboCache-like technology, dubbed AcceleRAM, that uses a fixed local framebuffer in conjunction with accesses to the system memory, resulting in a larger framebuffer at minimal cost. In most cases, onboard memory will be scaled down to no more than 32MB, with the rest taken from the system, as and when needed. We expect the ChromeS20 series to support 4X FSAA and 16X AF, and, interestingly, S3G makes reference to a multi-GPU technology under the MultiChrome banner. It promises open platform support with no physical inter-GPU connection between cards; simply plug into two PCIe slots, install the requisite drivers and away you go. Again, it's best-described as paper-talk until we see a final, working solution that's ready to ship to the masses.
2D and connectivity musings
All too often neglected by most when discussing 3D accelerators is the 2D feature-set that's available on modern GPUs. S3G's previous offerings have had robust 2D support, from video playback to connectivity. The ChromeS20 series supports hardware acceleration for high-definition video from both MPEG-2 and WMV HD sources that scale right up to 1080p. There's no mention made of H.264 hardware-based decoding, though, and it's something that we had expected to see present, given just how big an impact it will make on future media and the way it is encoded.
Connectivity-wise, expect to see retail boards outfitted with the regular assortment of ports. DVI, HD15, and S-Video will all be catered for, and we expect the ChromeS27 to ship with at least one dual-link DVI connector, thereby being able to drive the few displays with extra-high resolutions. We'll also have to wait to see if S3G adopts the high-definition connector of choice, HDMI, on retail models. Literature contends that the ChromeS20 offers up to 10-bit component modes, but this seems to be the resolution of the DACs and not, like ATI's Avivo, the entire resolution through the video pipeline. True 10bpc gives rise to around 1.07billion colours. All you need then is a true 10-bit display.
In common with both ATI and NVIDIA, S3G's Chromotion 3.0 engine also offers video scaling (4x4 in this case), adaptive de-interlacing, video de-blocking, and multi-display support.
Thoughts
On paper, S3 Graphics ChromeS20 GPUs take a step in the right direction. The basic hardware seems capable enough of challenging the midrange parts from NVIDIA and ATI, although we can't, as yet, tell just how good it will be in shader-heavy titles. The ChromeS20 initially comprises of two SKUs but a full product roadmap that includes desktop and mobile parts is sure to follow. That's the optimist's way of looking at. A pessimist would argue that S3G doesn't have the best recent track record when it comes to releasing new SKUs with the full software support they deserve. Just take a look at the lack of success 'enjoyed' by S3G's GammaChrome GPU. It, like the ChromeS20, has a solid hardware base that was floored by comparatively insufficient driver support and poor retail availability. S3G needs to ensure that its software support is every bit as good as ATI or NVIDIA's, otherwise the ChromeS20-series, full of potential, will be condemned to the kind of obscurity that the GammaChrome range is in. Having a larger number of card partners that are willing to market its wares wouldn't hurt matters, either.
S3 Graphics has the potential, if executed perfectly from both hardware and software viewpoints, to seriously challenge NVIDIA and ATI's dominance in the midrange 3D market and become the third major player in the sector. Only time and a complete review of the ChromeS20-series will tell if it's achieved it. We await a hands-on test.
