Black screen crash clue?

The subject "This tip really helps FS performance!!! is currently posted on FlightSim, AVSIM, and simflight forums. It recommends turning off hardware acceleration on your second monitor even if you aren't using one! I tried it and, subjectively, I think it helped frame rates/smoothness but I'm not sure how much. Judging by the forum posts and comments by Pete Dowson near the end of his documentation for FSUIPC, the problem of black screen crashes after you go from full screen mode to windowed mode and then attempt to go back to full screen mode is widespread. I have had it virtually 100% of the time. After I tried this tip, I wondered if it just might impact the black screen crash problem. It seems to - at least on my system. With this tip implemented, I was able to go from full screen to windowed and back without crashing AS LONG AS I STAYED IN FLIGHT SIMULATOR! If I did something else from windowed mode, I immediately and predictably crashed when I tried to go back to full screen FS. I am curious about: (1) Whether others who can use it might have the same experience with this tip? (2) If others do have it, whether it offers a clue (to those with a much more profound knowledge of FS9, XP, Direct X, etc.) as to what causes the black screen crash problem? Thanks