Kaap you have to admit the Nvidia cards took a hammering there.It's not even close. I know you like to tout titans with 6gb being the only 4k cards but most evidence so far goes against that. 4 way scaling being broke ain't much of a surprise in some games but surprised it is in Crysis 3 being a aaa title.
It's not so much that it's VRAM IIRC. 4GB isn't enough for max settings in that game when you've got the grunt to drive those settings.
If you want to drop settings then you can get good balances between the IQ and FPS (like you can in any game and graphic card) but as that is true anywhere it kind of becomes a moot point.