Computers are fast. Why do you accept a frame of lag? The average game for a PC from the 1980s ran with less lag than that. Super Mario Bros had less than a frame between controller input and character movement on the screen. (Technically, it could be more than a frame, but only if there were enough objects in play that the processor couldn't handle all the physics updates in time and missed the v-blank interval.)
If Vsync is on which was my assumption from my previous comment, then if your computer is fast enough, you might be able to run CPU and GPU work entirely in a single frame if you use Reflex to delay when simulation starts to lower latency, but regardless, you still have a total time budget of 1/30th of a second to do all your combined CPU and GPU work to get to 60fps.