System setup, specs., and notes
Hardware and Software
Test Platforms
Software
Need For Speed: Most WantedQuake 4
Black And White 2
X². Reunion
F.E.A.R.
Notes
Gaming benchnmarks were run at 1600x1200 and 1920x1200, both with generous levels of antialiasing and anisotropic filtering. You don't buy £350+ cards to run at 1024x768, do you? Adding in high pixel counts and extra GPU stress for enhanced I.Q. settings will make our selection of games restricted by GPU performance more so than any other factor. No problems to report during installation or benchmarking the cards.The obvious competitor to ATI's X1900 cards is NVIDIA's GeForce 7800 GTX 512, which isn't a 256MB card with double the framebuffer. Rather, its 550/1700 clocks are comfortably in excess of any 256MB version's. The troubling aspect for most gamers looking to purchase one is two-fold. Firstly, you don't receive much change from £500 for a single card. Secondly, retail availability is comparatively poor in relation to the number of vendors holding adquate stock of X1900 XT(X) cards.
What exactly are we comparing? Let's summarise the various GPUs' basic attributes in a table.
| Graphics card | PowerColor Radeon X1900 XT 512MB | SAPPHIRE Radeon X1900 XT 512MB | SAPPHIRE Radeon X1900 XT 512MB | PowerColor Radeon X1800 XT 512MB | NVIDIA GeForce 7800 GTX 512 512MB | Codename | R580 | R580 | R580 | R520 | G70 | Transistors | 384M | 384M | 384M | 321M | 302M | Shader Model compliance | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | Manufacturing process | 90nm | 90nm | 90nm | 90nm | 110nm | DirectX support | 9.0c | 9.0c | 9.0c | 9.0c | 9.0c | Core frequency (standard) | 621MHz | 621MHz | 648MHz | 621MHz | 551MHz | Vertex shaders | 8 | 8 | 8 | 8 | 8 | Pixel pipelines | 16 | 16 | 16 | 16 | 24 | Shader processors | 48 | 48 | 48 | 16 | 24 | Texture Mapping Units | 16 | 16 | 16 | 16 | 24 | ROPs | 16 | 16 | 16 | 16 | 16 | Memory frequency (standard) | 1,440MHz | 1,440MHz | 1,548MHz | 1,494MHz | 1,701MHz | Memory bandwidth | 46GB/s | 46GB/s | 49.5GB/s | 47.8GB/s | 54.4GB/s | VIVO support | Rage Theater | Rage Theater | Rage Theater | Rage Theater | Philips SAA7115H | Outputs (standard) | 2x dual-link DVI | 2x dual-link DVI | 2x dual-link DVI | 2x dual-link DVI | 1x dual-link DVI, 1x single-link | Display engine | Avivo | Avivo | Avivo | Avivo | PureVideo | Cooling slots taken | 2 | 2 | 2 | 2 | 2 | Multi-GPU technology | CrossFire | CrossFire | CrossFire | CrossFire | SLI | Average online price (inc. VAT) | £365 | £365 | £425 | £300 | £470 |
Note the identical specs. for the two X1900 XT cards from PowerColor and SAPPHIRE.
The main difference between X1800 XT and X1900 XT/XTX cards is in the extra ALU horsepower provided by 48 shader processors. R580s still have similar core speeds and memory bandwidth, and they're still based on a 16-pipe rendering setup with 16 texturing units, meaing that pipelines and shader quantities aren't going hand-in-hand with one another. What this also suggests is that R580's true worth will be realised with some present and most future games that rely on pixel shading to a greater degree.
There will be instances with older titles where R580, on a clock-for-clock basis, not looking any more impressive than the R520. What ATI has done, essentially, is re-designed a GPU with a view on where it sees games-development heading. Synthetic tests that hammer home the advantages of massive pixel-shading power will show the X1900-series in the best light. Something along the lines of ShaderMark and 3DMark06, for example, where the R580 GPU's 48 pixel shaders are set to work overtime. Considering that R520, a perfectly acceptable GPU before NVIDIA's GeForce 7800 GTX 512 stole its thunder, was launched last September and has been superceded so quickly, one has to feel for the early adopters who now see a version with significantly more bite, not from clock speed but via an shift in internal shader processing.
ATI's made the R580 faster, significantly so in cases where pixel shading is called to the fore, thereby effectively killing off its own X1800 line. Got £300+ to spend on a graphics card now, then? There's little or no point in considering a Radeon X1800 XT.
Overclocking
We were able to overclock both ATI Radeon X1900 XT 512MB cards to XTX levels without additional cooling, lending further weight, even though it's not needed, that X1900s are all derived from one common base. Further testing on the SAPPHIRE XTX model indicated that an air-cooled, stable core speed of 700MHz was a possibility.
