I had this issue when I was trying to get Grim Dawn to run on my Surface pro. It only happed on low resolutions though, like 1200x800 and turning anti aliasing off seemed to fix it. I don't know if its a windows 10 issue or an issue with my surface, but I solved most of my problems by dropping the resolution down to 1920x1200 both in game and through my computer's display settings, and also setting it to windowed mode instead of fullscreen. I'm not sure what you're running it on so maybe your hardware is way more equipped to handle this game then mine, but I can run everything at medium to high, as long as I keep shaders at medium and anti-aliasing off.

I use windos 8.1, have, 16GB RAM DDR3, nVIDIA Gforce gtx 970, im disable too the AA, im alwasys use FULL HD(1920 x 1080p 60 or 30hz on my samsung TV) nvidia drivers its latest, but witout AA combined with windows mode, fix the problem :), so many tnx :D

Try to delete gog galaxy and run the game without it. That worked for me without decreasing video settings

tnx i do :D, im using 1.0.0.6 Hotfix now.