Photos and official information on the Radeon HD 4800 have appeared on the Internet. These cards are based on an RV770 which has a memory controller with a width of 256 bits. This DirectX 10.1 GPU engraved in 55nm isn't revolutionary in terms of functions compared to its predecessor but it should enable ATI to seriously beef up its line with 96 vec5 units (or 480 stream processors) versus the 64 for the R600 and RV670.
The Radeon HD 4850 shown above has GDDR3 and a single slot cooling system. Power consumption should still be reasonable as a 6 pin connector and 450W power supply should be enough (550W for CrossFire X with 2 cards).
As for the Radeon HD 4870, it requires a fan which occupies an additional slot and it will have GDDR5, normally from Qimonda for the first models available in July. Note the presence if two 6 pin connectors while ATI recommends a 500W power supply or even a 600W for CrossFire X with 2 cards.
Finally, still no photo of the Radeon HD 4870 X2 which will be equipped with 2 GPUs although its cooling system already gives us a small idea of its length...
