Thanks. I’ve narrowed this down to the SyncRootManager feature in Windows 10. This is a provision that Windows provides to add a 3rd party sync point to Explorer. What I’ve seen is that having a certain setting set, which is specified as required in Microsoft’s documentation, will cause the slow moves. It appears to be a bug or byproduct of this feature.
It is possible that this entry is no longer needed, as my own, admittedly brief, testing shows it to no longer impact the overall functionality. Removing this entry makes same-volume moves very fast. We are going to expreiment with this, run it through QA, and see if we can live without it.
In the meantime you can remove the entry with this command run in a command prompt:
powershell -command "& { rm -Recurse -Path \"HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\SyncRootManager\odrive*\";}"
Currently restarting odrive will add the value back, so keep that in mind.