On paper, the R9 390 looks very much like the R9 290 that came before it. Indeed, it is based on the Hawaii GPU released back in October 2013. AMD has made some important tweaks to the Hawaii silicon that they now call Grenada. AMD has been able to add an additional base clock to increase pixel performance. They also changed the video memory from the previous 4Gb of 1250MHz DDR5 to 8Gb of 1500MHz DDR5, increasing texture performance. This alone should allow for greater performance at 4K resolutions and give the card longer flexibility.