Adi, > What I don't get: > Where is the third buffer? All three on graphicscard memory. two buffers for flipping, one as the replacement for the current visible buffer. > Why not just draw into the offscreen buffer then page flip? Because the third buffer will make the whole doublebuffer things 'invisible' to apps etc. The stuff will behave transparant, as if you would be drawing directly onscreen. That's also the reason why I think I can set this up inside the driver to work with standard R5. as the 'proof of concept'. I am not entirely sure if in the end some support is needed in app_Server or if I can keep it entirely local. (engine management gets more tricky) > Blit from front buffer to the back one so the two buffer be identical > at this moment. So, can be done, but adding the third buffer makes the whole setup 'transparant' to the system and apps, while without this a lot of app_server support is needed, and also BDirectWindow apps get into trouble (I think?) Bye! Rudolf.