Unless things have changed recently, i'm pretty positive that GSync doesn't work in SLI

Gameaholic wrote:
I have one ROG Swift and I'm planning on getting two more for triple gsync goodness. Right now I have a 780 Ti but that doesn't have enough Displayport outputs for 2 more Swifts. Mobo/CPU desperately needs an upgrade since I'm still on X58. So first question is X99 vs Z97 (Rampage V vs Formula VII), second question is 1x Nvidia Titan X, or 2x 980 or wait for 980 Ti? I see a bunch of 4k benchmarks for the new titan but from what I've read 7680x1440 is harder to run. 16x vs 8x PCIE lanes doesn't seem to matter but I kinda want to throw a pcie ssd in eventually. 12GB VRAM seems like overkill even at that resolution but 4GB doesn't seem like quite enough.

I would recommend a Z97 (with i7-4790K), you might even be able to re-use your DDR3. For what you want this is faster performance at lower cost. You could run a 2-way x8/x8 GPU setup and get excellent multi-display 4K+ performance - a pair of higher-end R9-280X/285 or GTX780Ti/970 cards would suffice, but badder is better.

The only compelling feature of an X99 platform (with today's parts) is the extra PCIe 3.0 lanes. Even a lowly i7-5920K (with up to x16/x8 or x8/x8/x8 GPUs) is nothing to scoff at, but you would gain more from a more expensive i7-5930K part (with up to x16/x16/x8 or x8/x8/x8/x8 GPUs). To be honest, even today's fattest single-GPU cards won't see a lot more performance across full PCIe 3.0 because they can barely saturate PCIe 2.0 bandwidths. You'd be paying extra premiums now to offset upgrade costs in the future (Q4/2015 or later), rather than just buying what you want, need, and can use today.

This is not the best time to buy high-end GPUs. If you can wait until Q2-3/2015 - when the Titan X has "mainstream" availability, AMD's R9-390X (along with the rest of the Rx-300 lineup) rolls out, and NVidia announces/releases some new GTX980Ti/990/whatever - then the pricing for current offerings will drop. Cost may be a lesser consideration, but a few hundred bucks per card might add up to a lot (maybe a full card's worth) when purchasing several units at a time. The sheer quantity of onboard VRAM is only a spec, a number - you can't actually use it outside of GPU-dedicated purposes - so it's better to ignore the marketing specs and focus on actual real-world fps performance. You shouldn't buy cards because of the specs unless those specs translate directly into meaningful performance.

korth. its mini dp ports and he needs 3 of those.
as per now the 980 have it on nvidia side ( including upcoming titan x )

The PG278Q ROG Swift comes with 1x DisplayPort input. Asus even includes a standard DP-to-DP cable.

A reference NVidia GTX 980 card provides 3 x DisplayPort outputs. Non-reference Asus GTX 980 Strix, Poseidon, and Matrix cards also each provide 3 x DisplayPort outputs.
A reference NVidia GTX Titan X card provides 3 x DisplayPort outputs. All GTX Titan X cards on the market (today) follow NVidia reference design.

My non-reference EVGA GTX 980 Classified ACX2.0 cards each provide only 1 x DisplayPort output, I cannot use two of these cards to display NVidia 3D Vision across three displays. I expect that some other non-reference GPU cards also provide non-standard output configurations - best to examine specs before you buy.

NVidia 3D Vision supports up to three identical displays. Up to four identical displays with the Titan X, if NVidia's advertising is truthful.

Mini-DisplayPort is electrically identical to "full" DisplayPort, it's just a different connector form-factor with smaller dimensions (less robust but becoming popular on mobile devices and crowded GPU backplanes, where size matters). mDP-output to DP-input (on the ROG Swift) requires the use of a mDP-to-DP cable or a passive mDP-to-DP adapter attached to a DP-to-DP cable. Sticking with "full" DP outputs offers no advantage nor disadvantage over mDP outputs, aside from saving you about $10-$20 each on extra cables/adapters.

mDP also happens to be the preferred output on most AMD cards, and these can support Eyefinity across up to 6 (identical or different) displays. But AMD GPUs do not support G-Sync and ROG Swifts do not support FreeSync, so you'd be paying a premium to buy two feature sets which cannot be combined.