Last week when my pc had a few more crashes I finally gave up waiting for the 1080ti and went next door and picked up a gtx1080. I have to say this cars fricken amazing compared to even the 2x gtx titans (original fermi I think it was so 780ti equivelant that I had) A single 1080 with my 6700k cpu and 16gb DDR4 3200mhz ram does much better then I expected. Shame the new Titan is both not available in OZ and also way over priced if it was probably $2k or something here. I think the 1080ti is likely due around christmas or early next year and even if its a slightly cut down titan x pascal but running faster clock speeds it will be a high res beast.
The 1080 I have easily does OC to 2050mhz rock solid and stable, its only limited by power so really cant get much more out of it. No point getting it on water as the stock windforce air cooler on it can keep it very cool at high load still. Cooling it any more would not help its oc as its simply power limited. I think there was an Asus card but $300 more then the one I got on special at $940 and in benchmarks it still seems limited to not much more stable oc around 2150mhz.
This card on my setup at 7680x1440 can just about max out both AC and Pcars, so in sli it should be able to do this with a fair bit more AA but really it looks great in both. I dont think with 2x old titans I could quite max the same as the 6gb memory was a bit of a limiting factor. Also at 4k most games I tried run at close to max settings not dropping below 60fps at all but just aa levels need to be dropped a bit which arent really needed on a 28 inch 4k screen anyway.
When the ti comes out I will consider maybe selling the 1080gtx and upgrading or maybe pick up a second 1080 and go back to sli as it should be quite a beast and at my res it will easily run anything in single screen 4k or 1440 x 3 for surround. The 1080ti if it gets 12GB of ram same as the pascal I think should be quite capable of doing 4k triple screen which would be amazing but for anyone not running very high res even the 1080 is likely more then they need for a quite a while.