Alt Tab out of the game after a mission is loaded, open task manager find the DCS32(or something similar) right click select affinity and choose which processor to use. I choose to use both and i get a huge performance boost around 10 fps (from 10 i get 20). You seems to have quad core i recommend in the affinity tab to select all processors available and if you face problems select the last 2.
You have to to this every time a mission is loaded.