There is no answer to this question? There are no callback hooks to time video card output. BUMMER bad form etc. The PC is really a messed up device when you need realtime hardware support. How cool would it be to have a simple callback interface? Geez I would imagine every game developer in the world would want one. So if I create a DirectX surface blt to it and try to figure out when it was sent I am on my own? I have tried to use WaitForVerticalBlank() but that was aweful and the results unpreditctable. So does any card offer this sort of feature?