ATI has already let it be known that they plan on shipping DirectX 11 cards before the year is up. Until now it has been thought that they would come later in the year.
However some new information suggests that ATI might be putting DirectX 11 capable cards on the fast track and they could be here as early as August or July. Information is still a little vague at this point but the cards will more than likely be based on RV870 and be 40nm chips.
This could give them a huge advantage over NVIDIA, at least for a few months before NVIDIA ships the GT300 series cards. Not only would they be in a great position to be king of the performance hill but would give those looking for an upgrade an additional perk for choosing an ATI card over the competition.