Adjust display refresh or Sync playback to display

So I am a bit confused on these 2 options.
So does :

Adjust display refresh rate..actual adjust your TV’s refresh to match the file’s video frame rate?

Sync playback to display…is this the opposite where you adjust the file’s video frame rate to match the TV?

Which option is best for smoother playback or better picture quality?
Should you set them both on?

Also for render method…which is preferred DXVA, Pixel Shaders or Software? so many options Big Grin

Thanks