Randy:
There are many possible causes for the sluggish behavior. You should make sure that you have the latest video driver installed from the manufacturer's website, the latest version of QuickTime, and the latest patch for PD11. If you attach a dxdiag to your next post, the folks here can take a look "under the hood" to see if there is anything obvious about your computer configuration that might be causing the problem. Instructions to do that are in one of the sticky threads at the top of this forum.
If you have shadow files enabled, turn them off. You shouldn't need them from what you have described of your computer configuration.
Without more information, we would all be speculating here. A dxdiag file would help to identify a possible issue or eliminate your computer as the cause. Also information on what type of files you are working with and a screenshot of your timeline would assist.
Hope this helps. Have a great day.
Regards,
-Phil
Windows 10 Pro x64
Dell XPS 8930
Intel CoreT i7 (4.6 GHz)
32 GB DDR4-2666 RAM
1 TB PCIe -x4 SSD
NVIDIA GeForce RTX 2060
PD14 Ultimate x64, 4207
CD4 Ultra and AD6 Ultra
Bleeping Computer Malware Response Instructor