Hello and thank you for your reply on this subject!
During the last few weeks I am writing MS Exchange backups to StoreOnce, too. So the amount of data has increased. However, It's clear that with that additional data Object Copy is taking longer but this should not cause StoreOnce to slow down X-Times.
Concurrency is set to 20 and currently 18 connections are active, still.
I don't know how to get this issue resolved...
Thanks for checking in the labs btw.