AMD’s RV770 XT will sport GDDR5 memory
We are getting back to the memory controller of R600, but possibly significantly improved and this time the chip can cope with GDDR5 while the previous controller could only cope with GDDR3 and GDDR4.
As GDDR4 didn?t really got these cards any faster, ATI decided to go for GDDR5. We believe this is the future and this definitely makes the RV770 a bit bigger than the RV670 and this will be the most significant difference between the chips.
NordicHardware add that the RV770 Pro will arrive earlier (around May), and only support GDDR3 memory.