And what about a year or two from now? 4GB if fine TODAY, but buying a $200 piece of equipment without thinking of the future is pretty silly, IMO.
GTA V, far cry primal, and shadow of mordor can all push 4GB at 1080p, with games like wolfenstein not far behind. When the 8GB upgrade is only $30 or so, considering it may get another year out of the GPU it's be just plain silly to get the 4GB version.
When I got my 770, I debated getting the 2GB or 4GB edition. People said the 2GB would be just fine.
Well guess what? two years later, and it struggles. Forza, GTA, SoM, Wolfenstein, None of those game can be maxxed out due to the 2GB limitation, while the 4GB versions can run them all no problem. If I had gone with the 4GB editions, I wouldnt be replacing my GPUs this year. To say nothing about SLI. In SLI, hitting the 2GB limit is painfully obvious. I have the GPU power, just sitting idle, because I only have 2GB of VRAM.
So yeah, 4GB is enough right now. But a year from now, not so much. better to have too much VRAM that goes to waste then having a GPU hamstrung by it's paltry VRAM.