Plastic SCM Client 11.0.16.7411
The pending changes view is unusable with a large changeset. It takes about 5 minutes to load (I have a NVMe drive and check content is disabled). Whenever I do something with one of the files through the Plastic client (like undo), the view refreshes again for 5 minutes.
Edit: Disabling auto refresh made things a bit better, it still refreshes on undo though. I will now switch to the Readonly-Workspace setting and hope this improves the speed.