OK so I solved my problem. In my project I accidentally had loaded a channel strip that I use for voice over editing that had stereo plug-ins (people sometimes send stereo files that edit and convert to mono later) on a mono channel with a mono file. Even after individually changing the plug-ins to mono the performance was still slow. However once I reset the channel strip and then individually reloaded new, mono plug-ins to replace the ones I had that were stereo the problem went away.
One odd thing I have found is that when I loaded another mono channel strip that I made for voice overs onto the mono channel the problem persisted. This makes me think that the second mono channel strip I chose was originally stereo and then I converted the plug-ins individually to mono within the project and then saved the channel strip. Make sense? Maybe it is a stretch but it seems that changing the plug-in state from stereo to mono and then saving it as a part of a channel strip is causing a problem.
I'll finish by emphasizing that if I rebuild the channel strip from scratch using mono plug-ins the problem is gone. It is also not a question of native versus third-party plug-ins because all of my plugins are third-party in this case.
Everyone have a great day.
