If you havent already I would suggest downloading Razer Cortex. All of Razers software is free and what Cortex does is suspends or shuts down (uneccessary) programs of your choosing when ever you start a game and frees that space so your computer has more focus on running the games you want to play. Once you know what you want to close, you can set this to "Auto-boost" when ever you launch your games. It also doubles as a game dashboard that will tell you what games are "eligible for auto-boosting', how many hours played and an fps chart. If it is a problem with your actual game, I would de-bug it or it may be as simple as turning LoL's graphic settings down.
[garen-swing]