Fuck its Gsync causing it? That explains everything.
My workaround has been to alt+enter during boot to deactivate fullscreen. Then you can turn it on again with the same keystrokes again. It never made sense to me why this would work but now it does, non fullscreen means gsync is disabled.
It started many patches and drivers ago for me and has persisted between my 970 and 980ti.
Thanks for the info ThoseDeafMutes i have tried what you have said about hitting alt/enter on the loading screen and it seems to works for me to.
Looks like it is linked with nvidia 9 series graphics cards and g-sync.
Did you try disabling g-sync to see if it worked for you?