X1950XTX is based on a new GPU, R580+, which is effectively an R580 that has been tweaked for operation with GDDR4. Memory speed is 2GHz!

Quote Originally Posted by www.elitebastards.com
Performance gains are modest but the price is killer and the revised cooler looks to be one of the best you can buy on any card. Price-wise, the new 1900XT 256MB ($279!), X1650 Pro ($99) and X1300XT ($89) are also very attractive.