Crashing in SR

Come on Riot this is silly. I crash 4 to 5 times every game since patch 4.20 and 4.21. I have a great computer and strong internet. What's going on??? Taking the fun out of the game.

My computer specs: iMac (27-inch, Late 2012) 3.4 GHz Intel Core i7 16 GB 1600 MHz DDR3 NVIDIA GeForce GTX 680MX 2048 MB