Posted here already by Dave
http://www.beyond3d.com/forum/showthread.php?t=25117&page=5
Just thinking out loud tho, the power requirements on that thing would be impressive. The power requirements on the ATI parts increase by roughly 90% adding 25% core and 50% memory and 256mb ram(XL specs to XT specs). This upgrade would be slighly more than that %wise for the GTX. So... 150 watts or so?