Hi, I made a little game with directX, which uses doublebuffering. The buffers are flipped with DirectDrawSurface->Flip after a DirectDraw->WaitForVerticalBlank. (Good old AMIGA method :P ) This works fine with Win95/98/NT but doesnt work with Win2k. The two buffers flicker heavily and it seems that DirectX doesnt wait for vertical blank.
What GFX/Drivers are you using? Some can disable "Wait on V-Blank", otherwise the GF2 would never get above 85 FPS (or whatever your monitors refresh rate is) for instance. I use Win2K at work (ie now), and the DX stuff I run hasn't shown a (noticeable) flicker. Mirno