Hexus posted a review on the AMD Radeon R9 280X vs. Nvidia GeForce GTX 770 at 4K
A quote from the article:
AMD managed quite a clever move last Tuesday. The company practically rebranded its current mainstream and enthusiast graphics cards from Radeon HD 7000 to Radeon R9/R7. Yes, there is a tweak here and there, but for the most part, the new cards bear striking similarity to those on retailers' shelves for all of this year. The kicker, as far as AMD is concerned, is the lower prices and improved bang-for-buck when compared to equivalent cards from Nvidia.AMD Radeon R9 280X vs. Nvidia GeForce GTX 770 at 4K @ Hexus
Appreciating there's nothing really that new this time around - we'll have to wait for the Radeon R9 290/X for a grounds-up architecture - it's with some interest that we hear AMD messaging '4K' for the best Radeons. That resolution assertion makes more sense for the upcoming R290/X cards, but there's no harm in evaluating how the premier R9 card for now, the 280X, handles a 3,840x2,160-pixel resolution.