AMD has just taken the wraps off of its new Catalyst Omega driver suite, which provides additional performance and a bunch of new technologies and features. The features built into the Omega drivers is extensive, but one of those stand out features is support for 5K displays.
5K you ask? What is 5K? 5K is 5120x2880, a mammoth resolution, which AMD now supports through its Omega drivers, even at 60Hz. 5K is achieved by using two DisplayPort 1.2 outputs, which some Radeon cards don't have, so you'll have to make sure you have two DP outputs before you think about buying that Dell UP2715k monitor.
5120x2880 is an incredible resolution, even overshadowing what 4K is capable of at 3840x2160 as it is an insane 14.7 million pixels, providing 218 pixels per inch, or PPI.