After the muted trumpetry of last year’s X1800XL, ATI has worked hard to create an upturn in performance. The results being the X1900XT and now the X1950XT – a considerable speedbump on the X1900’s R580 GPU.

Architecturally, there’s little difference between the cores: there are still 48 shader pipelines, and the die’s constructed on the 90nm process. However, the new programmable memory architecture is the crucial change, as the real performance overhaul comes in the RAM department. The X1950XT (codenamed r580+) sees the inaugural implementation of GDDR4 memory, and what a difference it makes.

Not only does its 512MB RAM run exceedingly fast – 2GHz to be precise – the lower latency and higher throughput of DDR4 make for increased memory bandwidth. This doesn’t noticeably improve frame rates over those of competing cards at the lower end of the resolution spectrum (say 1,280x1,024), because the CPU still bottlenecks each card’s performance at this resolution. The high end, however, is a different matter altogether. Up the resolution, and the card continues to perform, just when others start running out of oomph. At 1,920x1,080, no single card can compete with the X1950XT, and that includes Nvidia’s twin-GPU monster, the 7950GX2. What’s more, a pair of X1950s in Crossfire dualcard configuration offers altogether startling performance at the high end, making mincemeat of the muchvaunted Quad-SLI.

The card also features HDCP support for full-scale HD content and a new cooling block which runs considerably quieter than the X1900’s behemoth turbine. And it takes advantage of the latest Catalyst driver feature, temporal anti-aliasing. This is ATI’s new rendering system, which kicks in when the framerate of any given game tops 60FPS. Instead of every frame, every other frame is sampled at twice the AA level, enabling these frames to be rendered at 12xAA. As the frames are passing so quickly, the eye is fooled into thinking the overall anti-aliasing level is higher.

This card won’t support DirectX 10 gaming when the API hits along with Vista, but as far as DirectX 9 applications go, this is simply the most powerful card on the market.