why am i getting 25 FPS in 1 area of BO 1 then other 45 60 on Max out setting on a 1920x1080 1080p screen, 1 Geforce GTX 550 Ti, i5 2320, 4GB of DDR3 ram, DH67BL BORED, Intel 120GB SSD, 1TB HDD and Win7 i had it for 2 years now and i got it custom built I do not want to upgrade is there old drivers i can go back to or is that even going to work