League is having lag spikes in game.

I have been playing recently and been experiencing lag spikes in league of legends. At first I thought it was just my internet however all other games on my PC work just fine online. I even reset my router, and still there are spikes. Also my girlfriend plays with me in the same house and her game runs smoothly on the same internet. This past weekend my PC downloaded a microsoft update while I was out of town. I don't know if that is related but its the only thing that has changed about my PC since the lag spikes. Please get back to me at your earliest convenience.