would like to know if using fullscreen graphics is faster than having them windowed at the same size?
Considerably faster, on most computers.
Full-screen 3D is faster than the video card having to do both 3D in a window and 2D (around the window) at the same time.
On my computer things run about one and a half times faster in full screen than windowed.
Plus by default full-screen would run at 60 Hz on most computers, while in windowed mode you'll be running at whatever refresh rate windows is set to , which may be very different.