4k computer stutter when moving mouse fast

Okay this is a weird error and I didn't notice it until I started to play a large amount of games in 4k (after a recent computer upgrade).

I notice when I have a game in 4k, and I move my mouse slow.. the game doesn't stutter, but if I zip my mouse around quickly, the game stutters a lot, like the computer can't keep up with rendering the game and/or lagging.

Even weirder, it doesn't do it in first person shooters on 4k (because no cursor I guess?). The FPS's play smooth as butter.

So I am kinda at a loss as to what could be causing this.

I noticed it while playing Diablo 3, it lagged so much that I ended up going back to 1080p cause I thought the game was just glitch in 4k or something. Though now I am noticing it in lots of games after my upgrade too.

Windows 10 (with all updates)
i7 6850k @ 4.4
16gig of DDR4 2400
Asus Rampage V Extreme
Asus Strix 970s (2) in SLI (with latest NVidia drivers)

I just recently reinstalled Windows 10. And I note it was doing it in diablo 3 before I reinstalled Windows 10 and on my old computer.

Any help would be appreciated.

Microstuttering maybe. Try swapping with single GTX 1080 and see if the issues persist.