Ping?!??!

Every time I restart my PC I have to reinstall league for my ping not to be 400. My PC internet is fine I still get 50 MS to Chicago off of speedtest.net. Not to mention every time I alt-tab the game freezes for a good 2 seconds before it actually alt-tabs. This is only something with league nothing else on my PC is affected, and my PC can definitely run it.

Specs: Intel core i5 GTX 970 16GB DDR3 RAM