Techpowerup spotted ATI is working on a new RV790 based graphics card, the Radeon HD 4790. This new model will be slightly faster and a bit more expensive than the Radeon HD 4850.
Specifications-wise, the RV790 core runs at 600 MHz, slightly lower than the RV770 in Radeon HD 4850 (625 MHz), but its performance increment over it comes from the use of GDDR5 memory. The GPU makes use of a 256-bit wide GDDR5 memory interface. It handles 512 MB of memory clocked at 800 MHz (3200 MHz effective). Being based on the RV790, it is pin-compatible with any existing HD 4890 PCB. Price-wise, it is expected to sit between the HD 4850 and HD 4870.