Sounds pretty interesting
We learned some bits and pieces on ATI's upcoming RV790 chip and we can now happily confirm that his is yet another 55nm chip from ATI.
The company didn't want to postpone the introduction of the new card in performance segment and therefore did it in 55nm, while RV740 remains the first 40nm. RV740 just launched as a mobile chip, and we've seen it up and running, while the desktop part should arrive in the next month or two.
The new chip is a new architecture, but with some basic concepts taken from the RV770, that is why the chip will be significantly faster than anything based on the RV770. It is not just a speed bump and a better batch of RV770 based Radeon HD 4870 and 4850 chips, it is a newer and better chip.
It looks like this new chip will beat the GTX 260, and it could even get close to GTX285, but at a much more affordable price.