First of all, the X1950 XTX is not such a big upgrade from an X1900 when it comes to performance. This is more of a product refresh where existing weak points have been addressed. Most important, the new cooling system which offers quieter operation and lower temperatures.
The other major change is the move to GDDR4 which runs cooler and faster. Being able to run 1000 MHz real memory clock gives a nice performance boost. About 8% in the benchmarks. While this is not huge it is still nice if you consider that the same generation GPU is used on the board.
NVIDIA will not be happy to see such a product out on the streets going for $449. I think this card will be very interesting to people who are using an older card like an X800, maybe with AGP. If you are considering an upgrade to Conroe, PCI-Express and DDR2 the Radeon X1950 XTX might be just the right video card for you with its excellent price/performance ratio.
I liked that this card will work with the X1900 Crossfire Master. But since the master card is slower, the X1950 will not be able to increase your performance and run like an X1900 instead.
If you already own an X1900 you can definitely skip this update and wait for R600 which will be out at the end of this year.
If you want to go out and buy an X1950 card now, you are out of luck. This is a paper launch - the first cards will be on shelves some time in September. One of the reasons is that X1900 sales are good at the moment and ATI does not want to kill these sales.