The folks over at Expreview.com have uncovered an ATI roadmap that suggests that the performance Radeon HD 4830 part with be replaced with the all-new HD 4770 graphics card.
The roadmap seems to suggest that the new HD 4770 will have performance that's between that of the HD 4830 and HD 4850. The RAM will also be upped from GDDR3 to the faster GDDR5. For $99 that will represent a great deal.
Here's the spec of the HD 4770.
Something else that's interesting is that the roadmap suggests that the HD 4870 X2 will remain the top card until we start seeing DirectX 11 cards hit the market.