Hardware double buffering is provided for 8R windows on all the Creator accelerator configurations. Hardware double buffering for 24-bit windows is only provided on the Creator/DBZ (Creator3D) configuration. 8X overlay windows are never hardware double buffered on any Creator accelerator configuration; 8X windows are always software double buffered.
Activating hardware double buffering through MBX consumes one WID. This reduces the number of other WID-consuming windows that can be created. See "Hardware Window IDs"." If no WID is available, MBX falls back to software buffering mode in which a copy from a back buffer pixmap to the window is used to flip the buffers.
In MBX, the buffer flips occur synchronously. That is, the server request does not return until the vertical retrace period of the monitor occurs and the buffer is flipped. X11 clients may continue to run and send requests to the server, but will not be processed until pending buffer flips are complete.