Hello Nahrga
What causes screen tearing is when your frame rates exceed your monitors refresh rate. With out a G-Sync monitor V-Sync is the only solution to eliminate screen tear.
There are more and more monitors becoming available with G-Sync and 2015 is supposed to be a good year for monitors. As of right now with the limitation of display port 1.2 you either have to choose a 60hertz 4k monitor or 2560 x 1440 144hertz or the up and coming acer predator 34" widescreen 3440 x 1440 monitor with 144hertz and G-Sync which should be available in about a week or so according to the acer tech I talked to.
There is also talk of philips coming later in the year with a 32" 5k monitor.
So what it comes down to is what you want, a bigger 4k monitor with no G-Sync or a smaller monitor with lower resolution and higher refresh rate and G-Sync. As of now it's a limitation of display port 1.2.
This is the biggest 4k monitor that I know of that supports G-Sync at the moment.
http://www.amazon.com/Acer-XB280HK-bprz-28-inch-Widescreen/dp/B00O0Z5682You will need to sli your 980's to get decent frame rates on a 4k monitor, so with a single gtx 980 something in the range of 2560 x 1440 would be good like the ROG swift.
http://www.amazon.com/PG278Q-27-Inch-Screen-LED-Lit-Monitor/dp/B00MSOND8C