why does my card stutter in full screen D3D but not in a window?

[TravisBickle]

I'm mucho puzzled by this. I get stuttering in some d3d stuff like Xbtf. I don't know if it's in all d3d titles I haven't tried many, but wwii fighters did the same. no other programs seem to be interfering.

 

[TonyT]

What video card are you using? Have you tried updating the drivers? Did this just start happening? Did you change anything with your system (either hardware or software) recently?