|ATI Radeon X800 XT Mac Edition|
January 6, 2005 | Lucian Fong
ATI remained suspiciously quiet after demonstrating a Radeon X800 XT, their flagship GPU, in a Power Mac G5 at New York's Digital Life Expo in October 2004. They insisted that it was strictly a "technology demonstration" and no official product announcement had been made. Mac gamers who were hot and bothered by ATI's titillating statement can finally rid themselves of their angst; the Radeon X800 XT Mac Edition is here.
Boasting a massively parallel 16 pixel pipeline architecture — double that of the Radeon 9800 Pro — 256 MB of high-speed GDDR3 memory, a single slot cooling solution, and support for Apple's massive 30-inch Cinema Display via a single dual-link DVI port, the Radeon X800 XT is aimed towards the serious gamer and creative professional with a Power Mac G5. Even more noticeable is its $499 retail price tag, which is in line with its PC counterpart and undercuts its competitor, the NVIDIA GeForce 6800 Ultra DDL by a full $100. Interestingly enough, the MSRP is exactly the same as the GeForce 6800 GT DDL.
The Radeon X800 XT Mac Edition is shipping to retailers and should be available for purchase within the next week. ATI will also be demonstrating the GPU at MacWorld San Francisco 2005 at their own booth (#2217) and the Gaming Pavilion.
Below is a chart summarizing the basic specifications of the latest GPUs available from ATI and NVIDIA.
| Radeon X800 XT || GeForce 6800 Ultra DDL* || GeForce 6800 GT DDL* || Radeon 9800 Pro || Radeon 9600 XT* || GeForce FX 5200 Ultra* |
| Memory Buffer ||256 MB||256 MB||256 MB||128 MB||128 MB||64 MB|
| Pixel Pipelines || 16 || 16 || 16 || 8 || 4 || 4 |
| Vertex Units || 6 || 6 || 6 || 4 || 2 || 1 |
| Core Clock || 475 MHz || 400 MHz || 350 MHz || 380 MHz || 500 MHz || 325 MHz |
| Memory Clock || 1000 MHz || 1100 MHz || 1000 MHz || 680 MHz || 600 MHz || 650 MHz |
| Memory Bus || 256-bit || 256-bit || 256-bit || 256-bit || 128-bit || 128-bit |
| Fill Rate || 7.6 Gpixel/s || 6.4 Gpixel/s || 5.6 Gpixel/s || 3.0 Gpixel/s || 2.0 Gpixel/s || 1.3 Gpixel/s |
| Bandwith || 32 GB/s || 35.2 GB/s || 32 GB/s || 22 GB/s || 9.6 GB/s || 10.4 GB/s |
| MSRP || $499 || $599 || $499 || $349 || N/A || N/A |
* Specifications taken from manufacturer's website. May not reflect actual OEM core and memory clock speeds.
It's obvious that the Radeon X800 XT's specifications dwarf that of its predecessor and as such, it has set the expectation that it will outperform the Radeon 9800 Pro by a significant margin. Twice the number of pixel pipelines and a faster core clock speed should amount to a near doubling in performance, especially at high resolutions. Also of note is the 50% increase in vertex units — from four to six. This should benefit games that use vertex shaders like Halo, Knights of the Old Republic, Splinter Cell, World of Warcraft, and the upcoming DOOM 3.
ATI has also implemented GDDR3 memory, a memory standard that it helped to pioneer, though ironically, NVIDIA was first to put it to use in its GeForce 6800 Ultra GPU. GDDR3 has the advantage of running at much higher clock speeds than traditional DDR memory while maintaining lower temperatures. The Radeon X800 XT's memory is about 50% faster than the Radeon 9800 Pro, which will help when full scene anti-aliasing (FSAA) and anisotropic filtering (AF) are enabled.
ATI has decided to use slightly slower 475 MHz chips to ensure a steady supply of GPUs and to keep the price as low as possible. While the lack of a 500 MHz part is disappointing, using the faster chip would have constrained supply and made an already costly custom board even more expensive.
NVIDIA did not offer a product equivalent to the Radeon 9800 Pro in 2003, but this year, the GeForce 6800 Ultra DDL landed first and has held the performance crown for the last several months. But with nothing to compare it against, how do we know how fast it really is? Onward to the benchmarks!