Extremely slow transfers to NAS

I have a MacMini running Hazel that has a simple rule that when a file is added to the monitored folder, it moves it to a Synology NAS share via AFP mount. The connection between these systems is 1Gb ethernet and when I manually move a file in the Finder, it transfers at over 100MB/s.
For some reason, when Hazel moves a file, the fastest it ever goes is 20MB/s but more often it is extremely slow, like around 1MB/s. I just watched a 875MB file take over 18 minutes to move over to the NAS.
When this happens, I can manually move other files and it runs at full speed so it isn't a problem with the link, the disk IO, or either system resources.
Any idea what is going on here? There are no errors or messages in the Hazel debug log regarding slow transfers or other problems. Just normal messages but taking a long time.
Thanks
Hazel 3.3.5; OS X 10.9.5; Synology DS412+ NAS
For some reason, when Hazel moves a file, the fastest it ever goes is 20MB/s but more often it is extremely slow, like around 1MB/s. I just watched a 875MB file take over 18 minutes to move over to the NAS.
When this happens, I can manually move other files and it runs at full speed so it isn't a problem with the link, the disk IO, or either system resources.
Any idea what is going on here? There are no errors or messages in the Hazel debug log regarding slow transfers or other problems. Just normal messages but taking a long time.
Thanks
Hazel 3.3.5; OS X 10.9.5; Synology DS412+ NAS