Good FPS but gameplay not smooth...anyone else?

Hi folks,

did a test in COD with bomber interception mission (my plane vs one bomber), over the sea. I have 65 fps avg which is quite good (in this stage of dev.) but gameplay is not smooth. I dont have slideshow but its not smooth, its just like I have 25 fps. Anybody else experienced this? I know fps is not the only parameter to have smooth gameplay...but still.....
my rig: i7920@3.5GhZ (stock V), GTX470 TwinFrozr2 (OC to 750 on core), 6GB of RAM, X-FI Gamer, TiR 4 Pro....