Drawdowns fps when minimized the next game

I bought a new graphics card, gtx 1060 6 gb, it was a gtx 560 ti. Noticed the problem mostly when playing League of legends. First: fps is same as on the old map, but the map download 60 percent. Why is it not working 100 percent (about by the way is also not 100 percent loaded)? Second, when you minimize the game the fps drops dramatically and instead of +- 150 shows 90, even when the game unfolds. That is, I know when I have chosen, for example, the browser, the game fps will drop, that's clear. But, even if I will be back to play the game, the fps would still be less than when I stopped. And it happens even with high fps, there are micro freezes. Processor i5 2500k, overclocked to 3.8 GHz, the temperature was fine. Nothing heated. What could be the problem?
P. S. I Understand that percents are rather weak, but on the old vidyuhi was not like this when minimized. Sorry for the spam, already created a similar theme, but slightly not as described the problem.