Preview: S3 Graphics DeltaChrome S8 Nitroby Derek Wilson on March 9, 2004 3:44 AM EST
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The DeltaChrome S8 Nitro is a DX9 class card supporiting 2.0 vertex and pixel shaders sporting 128MB of ram. We have a few details of the S3 Graphics implimentations, but we have meetings scheduled with them over the Game Developers Conference (GDC) to learn the full details of their architecture which we will bring you in our final review of the card. For now we will tackle the basics.
The S8 Nitro has 4 vertex and 8 pixel shaders. The pixel shaders support both full and partial precision floating point (with full precision being 24bit per channel and partial precision being 16bit per channel). They are able to do up to 8 Z test operations per clock under the right conditions, they support what ATI and NVIDIA are calling 4x rotated grid antialiasing, and upto 16x anisotropic filtering.
Currently, S3 calls thier antialiasing algorithm 2xAA, but under 2x mode, the pixel is sampled twice both horizontally and vertically (which is technically correct, but doesn't fit the established standard). It is likely that the nominclature will end up changing at some point. The maximum resolution at which they support AA is 1024x768, and, eventhough the functionality isn't exposed, it would be possible to do 16 sample AA (what S3 would call 4xAA) at lower resolutions. Obviously this is not going to be fast, and it is unlikely that this functionality will be exposed in the shipping version of the product.
The cards anisotropic filtering may or may not end up being adaptive, but at this point things are still being sorted out. When the card ships, we will run it through the paces with the AF tester. For now, this will be a topic of discussion for our meetings over the GDC.
In testing the hardware we did notice a few visual glitches (which are to be expected from prerelease hardware and drivers), and S3 has assured us that they will be addressing all the issues we noticed. Of particular interest to us were the glitches we saw in DX9 titles as we are very interested in the quality of support the DeltaChrome architecture offers DX9 games. It is still too early to tell if the things we were seeing were due to limitations that can't be worked around or were just the normal run of the mill prerelease issues we were expecting to see. Determining the quality with which the DeltaChrome S8 Nitro will support the latest software won't really be something we can reasonably expect to do at this point.
S3 Graphics has indicated, however, that the type of DirectX performance we will be seeing in our preview will be in the neighborhood of what we will be seeing from shipping product, while OpenGL titles still have lot of room for optimization. The poor OpenGL performance others have seen from the DeltaChrome S8 non-nitro with previous drivers has been improved a bit, but S3 still assures us that they have a lot of breathing room. Again, this is only a preview and we will have to wait until we see final hardware and software to make a firm judgement on the OpenGL side of things.
The card we tested came with an analog, DVI, and video output port, and does not require external power. We also recieved an HD component output dongle that we didn't test for this preview. For the performance tests, the analog port was used.