Ì feel you lin0s, took me about a day or 4 to figure out what the fuck is going on, however it's still not fully healed.
Without youtube in the background soldat runs around 120 fps for me which is shit..compared to the 500/700 fps i should have, and yes it's definitely a huge amount of difference of the smoothness
I suggest you run youtube or a gif in the background anytime you play the game, atleast that works for me.. as for the smoothness the only tip i can give you is to search for small cpu taking processes in your task manager.
good luck!