I have been experiencing this problem to no end. I have gone forum after forum but cannot find the answer.
During the game, not champ select, I will get 1 to 2 second black screens but still retain game sounds.
They are very random, sometimes back to back, sometimes 5 minutes in between but it always happens over and over.
Brand new build, all drivers are up to date, DirectX is up to date.
I have tried the DPI fix but it only made it worse.
It seems this is a common problem without common fixes but if anyone knows the way please let me know.