Patch 4.19 nearly wrecked my computer!

My computer was running perfectly fine this morning, set up Netflix for my son to watch, was doing usual browsing while he went down for a nap. Then I installed the newest patch and couldn't even play any matches without EXTREME lag! So, I stopped playing, then tried to go back onto Netflix, but it would NOT work! I tried Youtube, nothing. Everything was loading excruciatingly slow. So I uninstalled League and bam, now everything works with proper speed again. I don't know what you guys did, but I am disappoint. I was trying to earn season rewards before the season's end, and now those hopes are dashed. Riot pls.