My entire pc lagging Whenever league updates

Title says it all pretty much.. Updates always get stuck at the end and u can't tell when it will update, but usually last around 10-15mins, my entire pc lags like this ONLY when league updates, does this happen to anyone else?

-This is also the problem when client crashes or something so it restores league to previous version so i have to download same patch again and its really annoying :s