when gaming at 1920x1080 1080p fullscreen whenever there is heavy action going on in game cpu gpu usage goes up, my screen would blink once or twice as if turning on/off v-sync but the blink lasts a little longer maybe half a second compared to actually turning on/off v-sync,I tried every connector on my asrock z97 extreme4 hdmi/displayport/dvi/vga.
I was using an older monitor via dvi 1280x1024 native res and no issues, I have tried most of the drivers from intel 3670, 4080, 4156.
I always reformat and install win 7 x64 fresh when trying out new drivers.