HCSn :
babernet_1 :
The just announced Fury X's should spank the Titan X's it seems. The Fury's have a full 4,000 cores compared to 3,000 or so for Nvidea. Time will tell though, we need to see the reviews.
With quad SLI or CF, the drivers will be a major consideration. Nvidea is the leader there.
AMD is still using GCN, though, and Maxwell is much more efficient overall. It may well "spank" the Titan X but I wouldn't bet on it just yet. Quad SLI or CF tends to have very poor support, especially in games, so it's kind of just a bragging rights thing at that point anyways...
The thing is, you can't judge GCN in general against Maxwell, because AMD's GCN is multiple architectural refreshes. The GCN in my R9 280X/HD 7970 isn't nearly as efficient as newer GCN cards.
True about Quad SLI/CF though. It's just for bragging. Terrible support, unless using GPU compute.