I love everything about Directory Opus (10.5.7.0, 64-bit), except for the very slow SFTP transfer speeds.
If I use an FTP client (Filezilla or CuteFTP have similar results), then my download speed is 43 megabits/second via CuteFTP (or FileZilla), vs 214 KB/s via Directory Opus.
I have tried changing the copy_buffer_size, copy_nonbufferio_threshold and ftp_copy_buffer_size, making them 512K, 0, 512K. Another test with 1MB, 0, 1MB. Another test with 2MB, 0, 2MB. All resulted in similar slow transfer speeds.
My SFTP upload speed via Directory Opus is actually not bad. I get ~900 KB/s average, which is about half of my total upload bandwidth. This is acceptable, and is roughly what I'm seeing in CuteFTP for uploads to the same SFTP Server.
My Internet speed is 110/23 (megabits per second up/down).
Yes. I have a problem with download speed as well.
What is particularly frustrating is, I switched my OS from Win 8.1 back to Win7 due to some compatibility problems with other software.
Only on 8.1 FTP was at full speed, i.e. same as I get via FileZilla, now in Win7 it won't go over 300KBYTES, FileZilla still gives me approx 9MBYTES.
I'm also experiencing very slow SFTP download speeds compared to those I reach with other clients. While WinSCP reaches 15 to 16 MBit and Beyond Compare 4 (a diff tool with FTP/SFTP capabilities) about 12 MBit, Directory Opus Pro 11.10.1 Beta x64 (on a Windows 7 x64 system) with Advanced FTP feature gets stuck at about 1.3 MBit when downloading a big file (I seldom transfer small files from or to a server, I mostly use archive files to speed up things).
I have a German VDSL connection with 25 MBit downstream and 5 MBit upstream. Using FTP, the maximum speed for downstream and upstream is almost reached; with SFTP, DOpus' upload speed lies around 3 MBit, which isn't brilliant (WinSCP as well as Beyond Compare both almost reach the maximum speed of 5 MBit), but I could live with it if necessary. But 1.3 MBit download speed really hurt.
In an older thread Greg asked a user to send a mail with the details. I set up a test account for you (maybe this is related to just some servers?) - is it okay if I send you the credentials so you can test it for yourself as long as you like? I really love Directory Opus and I'm using it all the time, and I don't like opening additional software for data transfers from a server. But being a web developer, I have to do this very often, and "unsecure" FTP is not an option.
In the old thread I linked to (it's closed now), leo said that there might be long-term changes regarding the FTP feature, but that was in April 2013... Is this still in the works?
I can confirm this. Uploading with SFTP is 40-50% slower (VDSL 50). But downloading is only around 10-20% of possible speed. For backup/sync I use SyncBackPro, which runs max. in both directions using SFTP.
[quote="Enigma"]I set up a test account for you (maybe this is related to just some servers?) - is it okay if I send you the credentials so you can test it for yourself as long as you like?
[...]
In the old thread I linked to (it's closed now), leo said that there might be long-term changes regarding the FTP feature, but that was in April 2013... Is this still in the works?[/quote]
Also, I'm not sure anymore what exactly happens there... I established an SFTP connection via ExpanDrive this time. ExpanDrive lets me use this connection via a drive letter (Z: in my case). The download was exactly as slow as if I was using Directory Opus' SFTP feature.
This confused me quite a bit, so I opened the Windows Explorer (Windows 7 x64) and started the download again. It was as fast as WinSCP. Huh? I'm no (S)FTP expert - is Directory Opus using its own SFTP component although ExpanDrive already established a connection? Or is it something completely different that makes the data transfer so slow?
My bet is your antivirus or firewall is causing the slowdown and treating or reacting to Opus differently to other apps, if the same 3rd party code is also slow in Opus and not in Explorer.
Could you try without them to see if that makes a difference?
It's also worth seeing what happens if you do the download in Explorer while Opus is also looking at the same destination folder, in case that triggers the antivirus behaviour. (Keep an eye on CPU usage while downloading.)
I already tried turning off both, but that didn't change anything.
That doesn't make any difference. I also tried dragging and dropping from one program to the other one, which lead to a normal download in the target program - fast in Explorer and slow in Directory Opus.
I didn't observe anything of interest when displaying the processes of all users in the Task Manager (sorted by CPU usage).
In Beta 11.10.4, SFTP didn't work for me anymore, no matter what I tried (see SFTP doesn't work for me in DOpus 11.10.4 Beta). Jon sent me a fix, and now SFTP not only works again, it's also much, much faster than before. Instead of a download speed of 1.3 MBit, I now reach just under 11 MBit - not as fast as WinSCP, but something I can work with.
ExpanDrive is still as slow as before, though, when I use it in Directory Opus. Not sure what is slowing it down that much.
Jon gave me the tip to play around with the copy buffer size ("Settings > Preferences... > Miscellaneous > Advanced > copy_buffer_size" or just search for "buffer" in the preferences window). Setting this to 512 KB (64 KB is the default value) made this approximately as fast as DOpus' SFTP feature now is for me - slightly less than 11 MBit. Consider me a happy camper!
I'm no (S)FTP expert - is Directory Opus using its own SFTP component although ExpanDrive already established a connection? Or is it something completely different that makes the data transfer so slow? 
