All I can say is that it would certainly make sense for AMD/ATi if this rumor turns out to be true. I really find it hard to believe that they'd enter the market with a new product like the 2900-series, knowing full well that it wouldn't compete with the best that the green camp had to offer without something else up their sleeves.

"According to Sapphire’s product matrix, Radeon HD 2900 XTX graphics board will feature 1GB of GDDR4 memory at 2050MHz clock-speed as well as the Radeon HD 2900 XT graphics processor at 740MHz with 320 stream processors."