I installed igfx_win10_100.7755 a couple of days ago and noticed no big difference. Today I upgraded BIOS to 81 and all of a sudden Graphics are very solid.
I have steamed Video in both Firefox and Edge chromium canary for a few hours now and also played a 50 minute 720P episode in VLC player.
All streamed on a 4K TV from a NUC7i5BNH via HDMI, absolutely rock solid has not blinked once.
I believe that it's BIOS 81 that did the trick.