Overall, there will be four cards coming into the market today. The Radeon X1900XTX, X1900XT, X1900 Crossfire, and the All-In-Wonder X1900. All four cards are equipped with the R580 graphics core, but are clocked at different speeds. The All-In-Wonder is a 256 MB card clocked with a 500 MHz core and 480 MHz memory.
The Radeon X1900 Crossfire master card has the same core and memory as the X1900XT. Of course the main differences are that it has a dual DVI link and Xilinx compositing chip, to make sure high resolution gaming is possible while in Crossfire mode. If you remember back to the X850 Crossfire launch, the compositing chip made some people unhappy, as it could only manage a maximum resolution of 1600x1200 @ 60Hz; high resolution gaming was not to be had with an X850 Crossfire solution.
The X1900XT and X1900XT Crossfire cards have a core clock speed of 625 MHz, and the 512 MB of GDDR3 is set at 1.45 GHz (725 MHz DDR). The Radeon X1900 Crossfire card will hit the market with a manufacturer's suggested retail price (MSRP) of $599, while the Radeon X1900XT will retail for $549.
The king of the castle is the X1900XTX. It runs at a core clock speed of 650 MHz and memory at 1.55 GHz. The clock speeds of the XT and XTX are slight but for those looking for cards that are guaranteed to run at the fastest speeds, you will have to spend the extra $50 for the 25 MHz in the core and 50 MHz for the memory. Of course, if you have to have the best, what is $50 in terms of bragging rights?