1. SLI really hasn't "arrived" for the 10xx series ... scaling is way way down as compared to previous generations. with 9xx, SLI averaged 70% scaling and 96% or better (sometimes over 100%) in the games where it was really needed. Today we are seeing:
2160p = 52%
1440p = 33%
1080p = 18%
There are many reasons or impressions as to why this "is what it is".
a) Nvidia has been working for several generations now to discourage SLI as with each generation, they are competing more and more against themselves.... 2 x 970 was 40% faster and same price as a 980 ... two 650 Ti Boosts were faster and cheaper than a 680 ... two 560 Ti's were 40% faster and $100 cheaper than a 580. They make much more money selling the single top card rather than 2 of the lesser cards so they have been gimping the performance of the lesser cards and shrinking the price differential to the top card.
b) The 1060 doesn't even support SLI and nVidia has no competition from the 1060 on up. The 1060 is faster than the 480 and when overclocked, the difference is speed is over 20%. The supposed price advantage for the 480 has no materialized and while you can CF two 480s, they cost more and can't catch the cheaper 1070.
c) Because of the above, it has been suggested that nVidia is purposely gimping SLI on the 10xx series until such time as improving it might offer a competitive advantage.
d) Some question exists as to whether DX12 will allow for as much of a boost in gaming compared to what SLI offers. As a result has / will nVidia continue to put time, money and effort into SLI development. Now that support for 3 / 4 way SLI has been officially dropped, this kinda lends support to the position that nVidia may not put as much effort here as they have in the past.
e) Given the above, how much time, money and effort will game devs put into SLI support with nVidia seeming to cut back.
That being said, at this point in time, it's hard to say what will happen... at least until AMD offers something in the medium to hi end range. While we have enthusiastically supported SLI from 5xx thru 9xx, right now I just can't feel comfortable either way.
2. By 2k I assume you mean 3 x 1440p. Truth is 1440p is "where gaming is at" right now. Here we have low lag, 165 Hz, IPS monitors that are delivering image quality with no motion blur or observable lag. Problem is only 2 monitors can deliver this experience and they both cost $700.... scratch that. demand has now driven the price up to $800
Acer XB271HU and Asus PG279Q
https://pcpartpicker.com/product/ttnG3C/acer-monitor-xb271hubmiprz
https://pcpartpicker.com/product/XvfmP6/asus-monitor-pg279q
With these monitors, you can run any game at 100+ fps using ULMB @ 1440p
Are there any other screens @ 1440p with low enough lag ? ... yes, but they aren't IPS
Are there any other screens @ 1440p with IPS panels ? ... yes, but the lag is too high and / or not 144+ Hz or no ULMB
The other thing about 3 x 1440p is this .... 33% more pixels
1 x 3840 x 2160 = 8,294,400 pixels
3 x 2560 x 1440 =11,059,200 pixels
So you are talkin' ... less than 60 fps in Witcher 3
3. The thing is... there is no ULMB at 4k .... at least not till January 2017 or so when 120 Hz 4k panels arrive. There's no cable that exists right now to carry the necessary bandwidth to that 120 hz monitor. So no I wouldn't invest in 4k as .... soon as 120hz models arrive, buyers remorse will hit new 4k monitor owners hard.
Yes, 3 x 1400p is attractive, but expensive at today's $2400 for IPS, 5 ms (real not advertised) lag, ULMB, IPS.
This should answer alot of your questions
http://www.pcper.com/reviews/Graphics-Cards/NVIDIA-G-Sync-Surround-Impressions-Using-3-ASUS-ROG-Swift-Displays
Facebook
Twitter
Instagram