Playback Cursor Jerky Motion

I've upgraded to Pro Tools 12.3 and am using El Capitan. All is fine so far except the playback cursor does not move smoothly across the screen. Rather, the motion is quite jerky and doesn't follow the actual playback audio smoothly or in very good sync. This makes it impossible to use it for finding edit points visually.

Anybody else seeing this, and are there any preferences that can be adjusted to bring the motion back to it's normal smooth motion across the screen?

Thanks in advance,

Tom Carlson

Playback Cursor Jerky Motion