A large part of that is the extra frame of latency added by the compositor. One experiment that I'd very much like to do is try to get Windows to promote a wind

A large part of that is the extra frame of latency added by the compositor. One experiment that I'd very much like to do is try to get Windows to promote a window to using hardware overlays (this is sometimes called "DirectFlip" but the public documentation on it is very sparse) and see how much that helps.