When I play on my Mac, 3-4 times per game the video will freeze. I can still hear the sounds, and I can fix it by tabbing out and back in again but it takes just long enough to turn a teamfight into a 4v5. I bought this computer brand new a week ago, I'm on Sierra, and I'm running no other programs but Firefox and Discord, so it can't be a memory issue.
I have the same issue, and it is quite annoying.
Hmm. I don't own a mac, but someone else posted about their new mac freezing yesterday which was responded to by a red. The fix might work for you. http://boards.na.leagueoflegends.com/en/c/help-support/EaudEZIo-bug-on-macbook-pro-2016
I contacted support and they gave me a bunch of steps to try. They were able to help me resolve this.
Solution: Turn OFF "Shake mouse pointer to locate"
System Preferences -> Accessibility -> Display -> Shake mouse pointer to locate
When I upgraded to my new computer, it turned this feature on for me. It was not active on my previous computer.
