Ever since minecraft 1.7 minecraft has been really laggy on my gaming pc it used to run at a steady 120 frames per second now it runs between 30-70 frames per second my Imac runs minecraft at 300 frames per second (which is above average for the mac) and my MacBook air runs at 70 frames per second (which is normal) my specs are Processer Intel Core i3 Graphics NVIDIA GeForce GTX 660 Ti 8 gigs of ram shouldn't minecraft run fine?
Added (1). Btw I have windows 7