What we know so far:

1- Same PCB (or at least very similar) as HD4870;
2- 2*6 pin connector;
3- 240Mhz (!!!) idle speed (I guess the rumours about the PowerPlay revision were true)
4- Same cooler
5- ATI OC Utility shows a max overclock of 1Ghz;
6- It's called 4890 and not 49xx.

Performance figures and design changes are only guesses right now.


And here's the first boxart:

I found it in Fudzilla. I don't know where they got it, though.