Well, higher than non-composited, non-vsynced X11 (but yes there are fun solutions like trying to render at the end of a frame to let the clients run ahead). But any reasonable major DE was doing compositing, and even minimal WM enthusiasts typically ran xcompmgr/compton/whatever because we're not in the Windows 95 era. Comparing to that, Wayland is much better, with direct async communication between the client and compositor, instead of Xorg acting as a glorified IPC broker that can get busy processing stuff…
Is that true?