ATI's graphics cards have established themselves through adequate gaming performance and exceptional multimedia capability, but despite their popularity their 3D performance has been consistently behind cards from Nvidia and 3dfx. While leaving headline-making to its rivals, ATI has been able to console itself with the profits made from selling huge quantities of cards to original equipment manufacturers. Times change, however, and ATI can no longer ignore the average consumer who now insists on exceptional 3D power from their graphics workhorse. Cue the Radeon, which ATI claims will compete with the best the competition can muster.
The feature list of the top-of-the-range card tested will do nothing to harm the company's reputation: a 350Mhz Ramdac, facilitating exceptional 2D performance at resolutions as high as 2048 x 1536 at 75Hz; a core clock of 183Mhz and a massive 64Mb of DDR RAM effectively clocking at 400Mhz; AGP 2x 4x; considerable DirectX8 support; and MPEG encoding on board thanks to the established Rage Theater chip and ATI's renowned DVD decoding. This is further complemented by both S-video and composite outputs.
For the first time, however, ATI's multimedia talents take a back seat to the feature set of the new Radeon CPU. Taking a lead from Nvidia's GeForce range, ATI has built an impressive Transform and Lighting (T&L) unit which it calls the Charisma Engine. This alleviates the CPU of a large percentage of the calculations needed for scene generation. However, it is the innovative HyperZ buffer that sets the Charisma Engine apart from T&L offerings that have gone before. HyperZ is an ingenious bit of lateral thinking which addresses the restriction on every graphic processor's performance - the lack of memory bandwidth. By creating a cache that prevents the unnecessary translation of needless polygons, ATI has come up with a way to reduce inessential accessing of the Z buffer thereby freeing up much of the over-stressed memory bandwidth. The product of this technology is a modestly clocked Radeon consistently outstripping the GTS 2 cards running at 32bit resolutions in excess of 1024 x 768.
ATI's design incorporates three rendering pipelines, each performing two texture operations per pass and giving a maximum of only 1.1 Gtexels/sec (183Mhz x 3 x 2), compared to the GTS 2's 1.6 Gtexels/sec. With this in mind, the Radeon's results at high 32bit resolutions say much for the new HyperZ technology. It must be noted, however, that ATI's product is way behind that of the GTS 2 in terms of 16bit performance. At that level, its streamlined efficiency is not as effective as the sheer strength of Nvidia's offering.
ATI has actually promised three versions of the Radeon for release: a 64Mb DDR with video in & out at £299; a 32Mb DDR at £189; and a 32Mb SDRAM at £129. ATI hope that this last variant will remain competitive thanks to the boost from HyperZ, and the full range sees the company attempting to have a finger in every tier of the 3D card pie.
The ATI card we tested showed impressive 3D performance and excellent multimedia functionality, and it will undoubtedly find a position at the top of every power-user's wish list.
The latest graphics cards are compared in a group test in October 2000's Personal Computer World.