Some of the features that may be running in the background can require computer processing resources. Things like the Orbits and Waveform displays get redrawn in real-time as the video plays. If these background tasks are complex, they can slow down the video playback. Make sure that any background windows are closed if they are not essential to the work you are currently doing.
NOTE - You will lose any ROIs which are currently active if you close the Spectrum Window, but since it is not redrawn during playback, we recommended that you leave the Spectrum Window open.