Multiple sources have told us that they learned RV790 might be branded Radeon HD 4890 and this card should launch at some point in April.
It is definitely going to be faster than Radeon HD 4870 and it beats GTX 260, even the 55nm one, and we are quite sure it will come close to GTX285 performance, but there is a realistic chance Nvidia might still be faster with the 285. Bear in mind that HD 4890 is the name that ATI is throwing to many people, but the company can change this in a heartbeat. They did it before with 38x0 when everyone expected a 2x00 generation card.
As we said last week, the RV790 chip is not the same as RV770, it has some architectural improvements and should run faster clock to clock, but we don’t know many fixed details. The notebook version of the chip is already out in the wild and it should be shipping in April time in Asus notebooks, which means that the desktop chip is much closer than many expected.
Did we forget to mention that the RV790 is a 55nm, not a 40nm chip?