Solved: Slow Transfer Speeds on Synology NAS

Solved: Slow Transfer Speeds on Synology NAS

So you’ve got a shiny new Synology NAS and you’ve started storing files on it, videos, music and so forth.  Unfortunately, the file transfer speeds are so bad you’re considering buying a turtle and glueing a USB drive to its back to speed up file copying.

After hours of searching the net for an answer, in the end, I found the cause of my woes in a couple of little settings tucked away on the Synology – effectively my Synology NAS wasn’t even trying to use newer/faster versions of the SMB protocol.

To find and check this, perform the following steps:

Login to the Synology NAS and click on Control Panel:


Ensure that the SMB service is enabled then click Advanced Settings:

In Advanced Settings, set the Maximum SMB protocol to SMB3, I also increased the minimum SMB protocol to SMB2.  If your NAS is operating on a private home network, you may want to disable transport encryption mode (use at your own risk) and enable opportunistic locking:

For me on my Synology DS215j, this took my file transfers from around 5MBps to around 80MBps!

Bob McKay

About Bob McKay

Bob McKay works at Perfect Image, is a father, programmer and a self confessed techie-geek type.

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22 comments on «Solved: Slow Transfer Speeds on Synology NAS»

  1. Margaret says:

    Is it necessary to reboot after making the changes? I have the DS218j. First I had used Disk Station to do a 2-way sync on my desktop for the Pictures folder. SLOW. Next I synced the Music folder. Relatively faster. Now I am attempting to sync the Music folder on my tablet (SSD) remembering how much quicker the transfer was on the desktop. File transfer rate = 1 file every 8 minutes. It’s been several days and 473 files remain. This is beyond painful. Many other descriptive words. So in short, I’d like to try these changes now w/o having to start all over because of a required reboot. Thank you!

  2. Margaret says:

    Got my answer. When attempting the change, “Network Service will restart”. Guess I need to be patient….

    1. Micheal Espinola says:

      For anyone wondering, you can do this live. Your time machine backup or file transfers will quietly recover from the extremely brief disconnect. Networking at this level recovers all on its own. You’ll quickly see your time machine backup estimated time drop soon afterward.

  3. Will says:

    Thanks! Just wanted to comment for others that might stumble upon this. Don’t have a gigabit router so was looking for other options to speed up my 1.5mb/s speed. This really worked – cut a 90gb move from 16 hours to 3 hours.

    1. Bob McKay says:

      Hi Will,
      Glad it helped! 🙂

  4. Matt says:

    I was really hoping that would be the answer to my problem… unfortunately it didn’t do the trick 🙁
    However, my settings wasn’t setup as you prescribe. So I hope that a step in the right direction.
    Thanks for that.

  5. Giordano Bruno says:

    Good morning. Your hint made my month!
    Slow speed has been a problem for years for the 1812+: the max. was 25 at its best …
    I was even considering changing it for a newer model.
    Now speed is up to 110 which is perfect.
    Again: Thank you very much and all the best for you and your family.

    Giordano Bruno

    PS What is the transport encryption mode? What if I unable it?

    1. Bob McKay says:

      Hi Giordano, I’m glad it helped! The transport encryption mode adds encryption to SMB V3.0 for security but obviously like any encryption, it comes at a cost so may affect your top speed it its enabled (try it and see!).

  6. Ming says:

    Very helpful. Save my day. Almost return. Synology should put this on their site

  7. Cub says:

    The hints not work for me, still only getting 10.5MBs max transfer,
    Any advise?

  8. Clay Burch says:

    I can’t even access my nas. It keep saying authorisation required. Any suggestions???

    1. Bob McKay says:

      Hi Clay,
      I’m afraid if you’ve lost the credentials to your NAS you have a whole other problem my friend!
      If you can browse to network shares though, your computer must have some saved credentials you may be able to retrieve.

    2. GC says:

      Clay, There is a reset button on the NAS. Use it VERY CAREFULLY. The Synology web site will say something like hold BRIEFLY and it will reset the password. If you hold it too long it will do a complete reset and you will lose your data. So please, READ the web site first.

      1. Bob McKay says:

        Hey GC, Thanks for the useful comment!

  9. Sanjay says:

    How long do I have to wait for the \\Diskstation share to come back? Currently says “The Network path was not found”…

    1. Bob says:

      Reboot the PC after the change. I had the same issue and that resolved it for me.

  10. Craig says:

    You legend!!!! Cant believe Synology don’t advise this info!

  11. Adam says:

    I recently purchased and installed a Synology DS418play NAS, using WD 4TB RED drives. After finding Mr McKay’s page on the interwebs,I made the same changes to my NAS as listed above.

    Yet, it hasn’t solved the speed transfer issues. When moving three (3) ~4GB files from a PC to the NAS, with the NAS mapped as a network drive, the initial transfer speed is great…some 106mb/sec (Ihave the two NICs bonded, on a gigabit switch). Then, within a few minutes, the transfer rate falls off a cliff, dropping down to 5-6MB/sec.

    It appears to be an issue during a multiple file transfer, not a single file transfer.

    1. Bob McKay says:

      Hi Adam,

      When you say the issue seems to be when you’re transferring multiple files, are they concurrent or queued? I’m wondering if concurrent copies of large files will have the hard drive head dancing back and forth and it could be the slow down you’re seeing is the caches maxing out. What is your RAID configuration and do you see the same problems copying the same 3 files back to your PC *from* the NAS?

      1. EB says:

        Honestly, I want to throttle the people who suggested I buy a NAS and the replacement supposedly ‘better and faster one’. What a waste of money. I’ve spent the last 5 days trying to upload, transfer and get everything running and syncing smoothly!

        1. Bob McKay says:

          Erm … thanks for the comment Em.

  12. MB says:

    Hi, thank you very much, I’ve been seaching on the web for couple of hours before finding your solution. It works for me!

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