Both Hard OCP and Tech Reports report that the x1900 XTX sports 48 pixel pipelines, a 650 Mhz processor, and 512MB of 1.5GHz RAM. The Xbox 360 also has 48 pipelines, a 500MHz processor, and 512MB of 700MHz RAM. It looks like ATI may have just one upped the custom GPU design they just sold to Microsoft.
The problem with computer games tends to be that only a couple games even try to take advantage of monster cards like this one; most of them go for the lowest common denominator, opting to build an engine that is scalable enough to look great on all manner of systems.
Here's the real kicker: the x1900 XTX commands a whopping $500 plus! For that price, you could get an Xbox 360 and have enough left over for a game and a Live membership!
[Via b Xbox 360]