I think it may have been the overclocked video card memory clock all along. With just the core and shader clocks overclocked, it seems fine. For whatever reason, all my other games ( including IL2 ) get kicks and giggles from my overclocking all three clocks but OFF seems to screw the pooch when I increase the memory clock!! Figures I'd have to have one angry dissenter. So I guess I'll have to fiddle with my overclock all the time just for this game.
I flew OFF an hour from the ground to up to 9,000 feet and never saw the weird junk with my memory clock back down to default speed. I only had it about 70Mhz higher too.