Leapfrogging is the name of the game with Nvidia and ATI in the graphics card market, but you'd usually expect one of them to claim the top spot for a while at least.

Since ATI announced Crossfire, its rival to Nvidia's SLI system for dual graphics cards, the company seems to have been in disarray. Having been assured that cards were imminent during the summertime, we still haven't seen widespread availability.

A week ago ATI said the Radeon 1800 XT was now in stock, but we haven't found a site with any available at the time of writing. To add to the confusion, different sites have given different availability dates. You can however buy the slower 1800 XL, and we've tested cards from GeCube and Sapphire.

Tests on reference cards showed it outperformed the Geforce 7800GTX, although not by much. But the 1800 XT is about to be knocked off the top spot already.

Nvidia has now slipped in the Geforce 7800GTX 512, and in tests in our labs, its performance has been impressive. You can read a full review, plus see its full performance results and compare it to other cards here.

As with the release of the Geforce 7800GTX, cards will be available immediately.