Setting Presentation Swap Intervals
A driver should always set the PresentationIntervals member of the D3DCAPS8 structure to zero when it reports the capabilities of its Direct3D hardware. The runtime then assigns the D3DPRESENT_INTERVAL_ONE value as the default. In addition, the runtime assigns the following presentation swap intervals depending on how the driver specifies capability bits in the Caps2 member of D3DCAPS8:
If the driver specifies the DDCAPS2_FLIPNOVSYNC bit, the runtime also sets PresentationIntervals to D3DPRESENT_INTERVAL_IMMEDIATE.
If the driver specifies the DDCAPS2_FLIPINTERVAL bit, the runtime also sets PresentationIntervals to D3DPRESENT_INTERVAL_TWO, D3DPRESENT_INTERVAL_THREE, and D3DPRESENT_INTERVAL_FOUR.