Consistently lower transfer rates than expected

Hello, first time poster here.

I came here to ask a question about speed, and I found this thread which seems to be about almost the same issue I have found.

In my case, we’re synchronizing two 5 GB folders, one in Europe (Windows) and one in South America (Mac), and although we both have a 40 MB/sec connection to the Internet, the transfer speed remains between about 1 and 4 MiB/s.

We both ran internet speed tests, which confirmed upload and download speeds of between 30 and 40 MB/s, but the transfer speed remains at around 1-4 MB, with an average of 1.5 MB/s in one direction and 2.5 MB/s in the other direction.

In my case we don’t see a higher speed in the beginning, but instead an average speed which is only 10% of what our connection should be capable of delivering.

Is this normal, or is there anything we can do to try and use more of the available bandwidth?

(P.S. Thanks to everyone here for this very well made and very useful tool!)

This does not seem related at all.

I suspect there are many prior threads explaining things, but if you still have a need to discuss it, please create your own thread.

In general, your internet speed to some local testing server has barely any relation to the speed you’d get when sending data half way across the globe.

In addition to what Audrius said, make sure you’re not mixing units. Internet connections are generally rated in megabits per second, while Syncthing defaults to megabytes per second, and you’ll see roughly a factor ten between the two (actual in-the-file bytes gain some overhead in becoming on-the-wire bits).

I took the liberty of moving your comment and replies to a new topic - makes it easier to keep track of the respective issues/details/info.

Besides what has been mentioned: Do you have a direct tcp connection? You can check the remote device address for that (or post screenshots if in doubt where).

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Thanks for the response, I am sure about the units.

I’m afraid I don’t know how to do that. If you can kindly point me towards a tutorial or something like that, it would be appreciated.

Here are some screenshots and whatnot:

Thanks, I think I understand what you mean, and it may explain the situation, but then again, I often access resources halfway across the globe at full speed, while in this case, in spite of having a direct connection, we never seem to reach more than a small fraction of that full speed.

I guess the only way to really test things would be to establish some other kind of direct connection between the two points (perhaps even FTP, or bittorrent, or TCP like someone else said and which I don’t know about) and then compare the speed of the different channesl.

Thank you, and everyone else, for the kind replies and suggestions. I’ll now take some time to follow up on the different leads, and I’ll make sure to post anything that I discover that might be useful to others.


Sounds like a good start.

As others suggested, I’d also verify you are actually connected directly, as Syncthing tries quite hard to get connected in many different ways, even if its not optimal.

The docs link above should cover it.

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