Smoothness is measured by frametime, not frames per second (fps).
You can have 300fps and shit experience.
It's possible for a single frame to take 100ms and the others take 10ms, resulting in 91fps.
But you will feel that frame hit you like a knife on your back...
If you use MSI Afterburner, WITHOUT D912PXY, you can try to put a graph with the frame times.
Also, check your hardware for overheating or underclocking. And make sure you use the right power profile for your hardware.