[CLIENT] After 6.4 alt tabbing takes sooo much time

Pre 6.4 , I could enter league alt tab change music or do what ever I want to do in a matter of seconds, after 6.4 it takes around 6 seconds to alt tab out and another 6 seconds to go back in. I don't think my pc is the issue since I have a beast pc. Pc Specs: i7 4870HQ 3.4 Ghz 32Gb Ram Gtx980M Windows 10 x64 League Installed on SSD