Erratic FPS behavior

[Sn8ke]

From my experience, this issue replicates itself within minutes in most multiplayer servers. I Have a core I7 CPU @ 4.9ghz and two 1080 GTC SC's in Sli. Gsync going on a 4k 28". After several minutes, my steady and smooth 60 FPS starts behaving erratically, jumping up to 70+, then down to 40's and back up to 60. When panning with Track IR 5, the screen doesn't tear, it just skips all over the place. I turned of gsync and used only Vsync...same problem. I turned off sli and used no NVI profile...same problem. Is this known and how do I fix this?