In the meantime I know that on the system where I suspected the issue to exist the I/O had a lot of issues unrelated to `garted`. It does no longer exist, but there seems to be no problem while copying with the tested block sizes after all. Thanks for your input.
** Changed in: gparted (Ubuntu) Status: Incomplete => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1396856 Title: block size limit for partition moving slows down fast devices To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gparted/+bug/1396856/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs