HyperBackup to another NAS on LAN is slow

[oRBIT]

I got an old DS218play to play with. The plan was to try to use that a backupdevice (currently on same network as my DS923+). I configured a backupjob to backup my stuff to the Play-device. However, transferspeeds are pretty average, something between 25-45MB/s (files are mixed in size). I know the DS218play is a bit ancient these days but are speeds like this expected?

 

[EAZ1964]

For mixed size files, this speed seems ok to me. Many small files bring back read/write speed considerably.
If setup as intended: Once the backup is fully done, your next backups are incremental and finished within minutes.