Hello guys! I want to setup some really performance focused gaming PC. Cash is not an issue – just want it to work better. First of all, it must be AMD GPU. Yep, I know that probably SLI 980Ti would be a better (and easier) choice, but still – AMD needed. Gaming PC with 3 (full HD/WQHD) or one 4k monitor. Should I go with Crossfire R390X (because of its 8 GB VRAM) or Crossfire R9 Fury X (because of better performance and HBM memory)? Thanks!