Only in as much as windowed mode always waits for vsync, even with flip 0. Well that is how it is on my system anyway, maybe XP is different. So its a bit difficult to quantify how much extra time the text display is taking given just a FPS because your code might be running close to a vsync and the text display is just enough to tip it over the edge and make it always wait for another one when you flip. So for a comparative FPS you really need to be running without a wait for Vsync.
More generally though my understanding is that displaying text or any 2d stuff is likely to stall the 3d graphics pipeline, though I would have thought that would make for more obvious differences full screen than windowed, but then I do not really understand exactly what DX is doing to support a window so who knows.
All I can say for sure is that for the same refresh rate windowed mode is usually somewhat slower than full screen on my system, no doubt for a variety of reasons.
More generally though my understanding is that displaying text or any 2d stuff is likely to stall the 3d graphics pipeline, though I would have thought that would make for more obvious differences full screen than windowed, but then I do not really understand exactly what DX is doing to support a window so who knows.
All I can say for sure is that for the same refresh rate windowed mode is usually somewhat slower than full screen on my system, no doubt for a variety of reasons.