[solved] 1.2.x slow as in the 90s when 1.1.81 is fast (Win 64bit)

Recommended Posts

I get slow downloads with the 1.2.x windows builds.


If I use btsync 1.2.71 on Windows my average download speed is 10 ko/s with occasional spikes >500ko/s,

while if I install back btsync 1.1.81, I get a solid 3.5 Mo/s download speed.


My setup is as follow:

  • Windows 7 64bit, Intel I7 920 + 9Go RAM hosted at home
  • Raspberrypi hosted at home running btsync 1.2.71
  • Ubuntu 13.04 server Intel® Atom CPU D425   @ 1.80GHz, 2Go RAM,  hosted on a datacenter, running btsync 1.2.71
  • Ubuntu 13.04 server Intel® Atom CPU N2800   @ 1.86GHz, 4Go RAM, hosted on a datacenter, running btsync 1.2.71

My home Internet connection can give me download speeds up to 2.5Mo/s.


The linux x64 and ARM builds aren't the cause of the slowness as I can get good expected download rates when using 1.2.71 for all linux and ARM machines while using 1.1.81 on the windows machine.

Only when the Windows machine uses the 1.2.x builds does it get slow download speed (even from the raspberrypi which is on the same LAN)


  • Does anyone else experiences such slow speeds with 1.2.x compared to 1.1.x ?
  • Is this a known bug ?
  • Do you need me to try anything or submit logs to help figure out the root of the issue ?



Link to post
Share on other sites

I'm utterly frustrated with the latest 1.2.x builds for the same reason. My setup is two Mac Minis, one on 20/20 optics, another on 7/1 cable. Syncing a bunch of large (1GB+) files. 


Attached is the current BTSync upload performance on the 20/20 line. It's truly like back in dial up times.


Link to post
Share on other sites

One thing that could impact your data transfer is the relay server, which is enabled by default for every shared folder. Some also had improved transfer speed when enabling TCP for LAN only syncs, see the advanced settings.

my options are :

  • no relay server
  • don't use tracker server
  • do search LAN and DHT network
  • use predefined hosts (and on each of my btsync, I put the addresses of the others)

I did set up TCP on LAN as well as I disabled encrypting data on LAN.


But anyway how can any of that explain such a difference between 10ko/s and 3.5Mo/s ?

Link to post
Share on other sites


This version has improved things a bit on my side, I mean, the transfer speed increased from 80kBs to 115Kbs, but I still find that quite slow.

It's about 10% of the network upload capacity where I currently am.

The download transfer speed on the target machine location is much higher that this.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.