CEngine::Frame() tends to return out early if we are ahead of frame time, and therefore need to sleep. In this particular engine, CEngine::Frame() returns true if it had actually executed an engine frame, else it returns false.
Therefore, we end up calling 'NvAPI_D3D_Sleep()' multiple times a frame, and thus causing a major loss in performance. Now we check if we have actually ran a frame (incrementing reflex frame if so). If the frame was not incremented, but 'GFX_RunLowLatencyFrame()' was called, it will not call 'NvAPI_D3D_Sleep()'.
Code has been tested and appears to work on my system (never called twice or more per frame). Needs more testing on other systems to make sure its good.