TweakTown is pretty certain that we will see a new HD 2900 XT card in June. This card is supposed to have 1GB of GDDR4 memory and will be under 10 inches long. In a [H]ard|Forum thread on this subject, [H]ard|OCP Video Card Editor Brent Justice said:
"I am 90% sure they will kick out a 1 GB GDDR4 version. I am also 90% sure that version will not have much of a frequency increase, if at all. It may simply be a 2900 XT with 1 GB of RAM, which would not improve performance in games. Think 256 MB 9800 Pro.
We will see though, GDDR4 would help bring the power utilization and heat down very slightly, but I don't know if it would be by any noticeable measure."