Client Issue

I dont seem to find a solution to my problem. So the client works really slow, just by swapping between "profile" "collection" or "shop" takes like 3 seconds. And same goes for creating lobby etc... In champ select choosing a champ takes about 3 seconds aswell and every mastery i choose takes 3 seconds before they show. And as soon as i enter game the issues are gone. I have all my drivers up to date, reinstalled the game, low spec mode on. Nothing really seems to fix the issue. The only thing i've manage to do to fix it. Is to only give acess to 1 processor core on "Leagueclientux.exe and Leagueclientuxrender.exe" But as soon as i close client and reopen it i get bugsplat and have to reinstall the game.

Ps: I have a computer good enougth to run any game on ultra with good fps, i cant see how client would require more than a game on ultra.

Thanks in advance.