U.R.F. having issues on my Mac

Hi, is anyone else that has a mac lagging in league to the point that the screen ends up blacking out?

First it started by the champion skating in lane, then it proceeded to jump through the screen, and lastly it all went black and a white spot came out seconds before it disconnected me. This has happened to me two times in a row in the U.R.F mode. One of the times I was able to enter before the match ended but the second time I couldn't. In the second time, once I came back my screen still had the black and white spot with only the chat visible. I hope this can be fixed or checked because I really like the URF mode. Thank you for reading this!