Its just TF2. I have a AMD 965 BE (OC at 4.1) with 16GB DDR3 1800 RAM and an ATI-7970 graphics card. I still have trouble maintaining stable 120-130 fps. Oh and i use dx9frames config too.
I play BF3 and Blacklight Retribution at 250-290 fps but tf2 jumps anywhere from 55 to 170.