On Sapphire's website the x1900 and x1900 xtx specs are revealed.  The x1900 xtx will have 48 pixel pipelines a 650 mhz graphics core and a 750 mhz (effective output 1.5 ghz). 512 mb of memory will be in this baby, but price is not revealed on the website.  512 mb of memory will probably be more common on high end cards in the future, but it will be a while until we see it hit mainstream cards on the market.  This card has higher specs than the Xbox 360 gpu so it looks like the 360 is out of date at least if your comparing it to a single card solution on a PC.  I saw it the specs for the x1900 on the website, but they disappeared when I visited it again so it looks like it was accidently released too early.  Who knows if they're hiding somewhere.