S4 Features

In case you’re not familiar with S4, we’ll provide a quick refresher, then get into image quality observations.

S3’s S4 DeltaChrome is a true DirectX 9 part, with support for 2.0 pixel and vertex shaders and floating point data formats. Like ATI’s DX9 offerings, S4 supports 128-bit vertex precision and 96-bit pixel precision, the minimum required for full DX9 compliance.

Borrowing a page from ATI’s playbook, DeltaChrome can use its pixel shaders to apply all kinds of cool post-processing effects to video signals (MPEG 2/4, Windows Media, etc). Neon edges, soft focus, sharpen, and emboss being the current examples. DeltaChrome even has a de-blocking filter, which can be used to clean up Internet webcasts. These features fall under S3’s “Chromotion” video engine and can all be adjusted in the current DeltaChrome driver as part of S3’s “screen toys” under the S3Chromo tab.

Top of the card

The back

Basically, S3 isn’t pitching DeltaChrome as a benchmark-crushing 3D powerhouse, but a solid all-round card. You’ve got good, playable 3D performance, more than capable 2D and DVD playback, excellent multimedia and video capabilities, and even the ability to drive HDTV; all HDTV resolutions are supported and a component video output (YPbPr) is provided.

In order to make the S4 affordable to produce for the value market, S3 has trimmed the number of pipelines in S4 from eight in the S8 DeltaChrome, to four in the S4 line. Each pixel pipeline is paired with one texture unit for a 4x1 pipeline configuration. For added triangle-pumping prowess, S3 one ups NVIDIA by integrating dual vertex shader units on the S4, double that of GeForce FX 5200. This should theoretically give S4 an advantage in systems with slower CPUs.

Two S4 cards are currently planned, S4 Pro and the faster S4 Nitro. We don’t have final clocks for the Nitro, but the S4 Pro is clocked at 300MHz core and 300MHz memory (in comparison, GeForce FX 5200 Ultra is clocked at 325MHz core/325MHz memory). In order to further reduce manufacturing costs, TSOP, rather than BGA memory modules are used, as well as a four layer board design.

Memory configurations will range from 64MB-256MB, with the graphics core featuring a 128-bit interface to the card’s memory, although we wouldn’t be surprised to see someone ship a very low-end 64-bit S4 card if the market demanded it.