I have just tried Bitvise SSH Client (Tunnelier)
so much better

I am converted

I'll consider rolling back the "default to Blowfish" change.
AFAIK, PuTTY (WinSCP uses PuTTY code for SSH implementation) does not use AES-NI. I suggest you propose the change to them.

I also noticed that 5.0.7 is much slower, with blowfish I can achieve only around 4MB/s max, with AES I'm getting 10MB/s on 100Mbit network, but cpu usage is very high. Is winscp using AES-NI instruction set on cpus which support them?

There's handly any change between 5.0.5 and 5.0.7 that might cause this. Except for Blowfish being default in 5.0.7, but that should actually increase speed. Can you email me a log files from 5.0.5 and 5.0.7?

You will find my address (if you log in) in my forum profile.

I must admit 5.0.5 was fastest version I ever used. 5.0.6 is slower and 5.0.7 is as slow as 4.x for me. Working on 100Mbit LAN, in SCP mode with Blowfish encryption I am getting <500kb/s 5.0.5 was 2-3 times faster.

For very few users with the increased buffer size, WinSCP stopped working altogether. Likely due to network misconfiguration on their side. As 4.3.x GUI is frozen, I could not add configurable option to disable the increase, so I pulled it.

Hope so. Just test it and you'll see for yourself.

Lastly.. why was the increased buffer size pulled from the 4.3 branch?

I am leaning towards using the 5.x beta version within production, but the retraction of the buffer code has me a bit worried.

Please advise.

"reasonably stable" enough to introduce into a production environment?


thanks for your response.

It is reasonably stable. Though not as stable as 4.3.x yet.

I use WinSCP(sftp) as the transport agent within my file ingest framework. Would you consider 5.0.5-beta production ready? Stable enough?

The increased throughput in this version is significantly greater than the throughput seen with current stable(4.x) branch.

what is the max speed that is possible? i am on gigabit internally and i can manage 9.1MiB with sftp to my server. running the newest beta 5.0.5.
thanks

Thanks a lot for feedback!

I can confirm that 5.0.5 build 1782 has solved my speed issues as well (and quite nicely, at that). My SFTP uploads have traditionally struggled to hit 400 Kbps on a very large pipe, and now they easily reach 9 Mbps. Thanks so much!

Likely due to this change:
http://winscp.net/tracker/show_bug.cgi?id=690

Thanks for sharing your (positive) experience.

It's implemented already:
http://winscp.net/tracker/show_bug.cgi?id=17
http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/flow-control-filexfer.html

Just wanted to chime in with my experiences with this issue..

Currently using 5.0.5 Build 1782 and not having speed issues, able to upload at my connection's max rate (~500 KB/s). However 4.3.5 and 4.3.6 were being mysteriously being capped at about 50 KB/s for some reason; I had all limiters that I could find disabled.

Another wrinkle to the story is this machine had its hard drive replaced on 12/26/11 with a fresh OS install. The previous HD/OS install with WinSCP 4.3.5 didn't have the above issue, however WinSCP was originally installed with 4.2.8 or 4.2.9 (going by WinSCP release dates and remembering when I RMA'ed the HD).

Would this work help lead to a faster implementation?

http://www.psc.edu/networking/projects/hpn-ssh/

WinSCP version:
5.0.5 Build 1782

While doing FTP synchronization remote local docs / remote docs

While in the GUI or running from script, receiving file transfer speeds from
10KB-500KB but averages around 100KB-300KB,
I can run other utilities and they transfer at 5MB+

FTP is the only protocal that can be used but it is definately being limited in WinSCP somewhere.

On another note. I do get many timeouts when doing a compare before the synchronization starts transfering files... causing it to timeout. Is there a way for the compare to continue on reconnect as do file transfers?

Can I ask all people posting here to mention version of WinSCP they are using? Thanks.

still it's not normal openssh's scp and filezilla to be faster on the same conditions

its not only firewall, its also antirus software, often they come with a firewall build in.

to check for it is to look at your system tray if any firewall or antivirus software icon is located there and into your "installed software" section and search for it.

what to do after you found it:
if you are in a safe environment (no internet connection, additional hardware firewall) you can try to disable / deinstall your security software (check if you have a installable version allready downloaded / on your harddisk before deinstalling!). then reboot and make all the speed tests again. also in some security software you can configure how much is filtered/monitored. so you can disable some realttime scanning stuff but keep the rest of the software active.

but i would never use a pc without antivirus / firewall softeware, i pay the price of extra security with a slower network speed.

best speed i got with linux to linux unencrypted file transfere without firewall
windows7x64 was slower in general (don't know why)
my firewall http://www.agnitum.com/products/security-suite/index.php / http://free.agnitum.com/ which i think is a great software if you want to have detailed control over your programs, reduced my transfere speed a lot (can't remember the exact numbers)
in combination with winscp the speed is quite slow (have not tried the protocol switch to scp and the change of the encryption algorithm).

i live with the slow speed, because for me security is more important than speed.

if you have speed problems and can determine that the firewall is the reason for it, you also can contact the software company who made the firewall and tell them what tests you made and that your are not pleased with the result.

Hi!

I have the same problem. I used WinScp 4.2.x and upgraded to the latest version 4.3.5. Here are results when coping to a server with bandwidth 10MBit/s:
scp.exe from git installation: 1.1+ MByte/s
ncftp (ftp protocol): 400 kByte/s
Filezilla (ftp): 1.1+ MByte/s
Filezilla (sftp): 1.1+ MByte/s
WinScp with scp protocol: 50 kByte/s
WinScp with ftp (no encryption) protocol: 200 kByte/s

PC used: Intel Core i7 2600 / 3.4 GHz. Can encrypt a lot more than 1 MB/s
All test are done in the same time, from the same pc, to the same remote server.

So if scp from mingw/git installation can copy with full speed, why WinScp can't? WinScp is 2 times slower than slowest scp/ftp client

Edit: WinScp 5.0.5 reaches 470 kb/s with scp and about the same speed with ftp. Maybe it's good to make these buffers editable or download source of openssh scp client and see what's the buffer size in it.

How do I check for this? And if found, how do I correct this?

don't forget to check if your firewall cause the slow speed. i also had speed problems and partly my firewall cause the loss of speed.

At least--and I'm searching for the good here---WINSCP has this great feature to shut down the computer when it's done. That's a good thing.

For me there was only a marginal speed improvement with using SCP instead of SFTP both using AES transfer protocal. I got a big speed boost however by changing the tranfer protocal to blowfish. It was slightly more than 2x speed improvement form 1360 KiB/s to 3100 KiB/s.

Please try 5.0.x beta. It has this fix included:
http://winscp.net/tracker/show_bug.cgi?id=690

Hi,

has anything happend regarding speed lately? I just installed the latest version (4.3.5). Downloads are still so slow that WinSCP is hardly usable for more than a couple of files. FileZilla has other issues, but is super fast in comparison. Of course I read the FAQ and most of the rest of this thread. Didn't help.

Cheers, Ralf.

Tunnelier is so much faster than Winscp (3x) with same hardware, same network, same copy job...

Tested version 4.27 versus Filezilla 3.2.7.1 and got near-as-dammit same transfer speeds to a local box over wireless ethernet (SFTP or SCP made no difference in WinSCP, Filezilla only support SFTP).

Hi,

I need to connect to sql server database from winscp.com , is there a way . I could find call statement is present. BUt i donr know hoe to connect to database to get some information from tables .

actaually i am getting information from text file .

open user:password@example.com
cd home/asuser
get *.txt D:\max\

Instead of getting info from file , i am planning to store these info in sql server tables and get the info from tables to this winscp.com.

please let me know if you find any way along wth the example

Thanks
Raghav

If i am not mistaken, WinSCP's SFTP/SCP code is based upon PuTTY's code which has had this performance bug for ages now. Actually all applications that use the code from PuTTY have this issue.

I tried t ouse winscp to copy files over to my virtual machine (Host Win XP/guest debian 5) over ms loopback interface....
Authentication takes ages, the transfer starts slowly enough to time out
(odd thing: when transfer finally picks up you can see it on the progress bar ... below the dialog with the ignore/abort choice - dialog should vanish in this moment, shouldn't it?)

To sum up the transfer is very uneven up to 3 mb/s at moments, often stalls.
Cygwin's scp 15MB/s steady.

SCP 4.2.6 build 721

Regards,
Maciej

I have an 800mg file on Unix that I was attempting to transfer via WinSCP to Windows.
SFTP = 470kbps
SCP = 1400kbps

so I ended up using Filezilla at SFTP = 4.4mbps.

Still using WinSCP because of some of the extra features ie. command buttons etc. but Filezilla is catching up, esp when it comes to the file transfer speed.

WinSCP does more or less the same.

FileZilla (SFTP): ~1.1 MB/s (unknown)
WinSCP (SFTP): ~300 kb/s (aes)
WinSCP (SCP): ~800 kb/s (blowfish)
Cygwin/OpenSSH 5.0p1 (SCP): ~1 MB/s (aes128)

Btw, my bandwidth over cable is about 2.2 MB/s (which I get when transferring over HTTP).

If you look at the debug output of scp (cygwin), they set some socket options and make TCP adjustments:
debug2: fd 3 setting TCP_NODELAY
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 2097152
debug2: channel 0: rcvd ext data 44
Sending file modes: C0644 52428800 testfile
window 1998780 sent adjust 98372
debug2: channel 0: window 1982464 sent adjust 114688
...

I don't know if WinSCP does that, but if not, that would explain the performance loss.

Tried both sftp and scp ... in fact, in contrast to some reports here scp was actually slower than sftp ... (1.5M / .8M). Copying via scp from linux to linux resulted in 5M, so the line (STM1) as well as the source server were fast enough ... transfer was download from the server ...

Tried tunnelier, and got around 8-10M/s ... (!)

Thanks. What protocol have you used? Was it upload or download? (if that matters).

Something I have noticed when running WinSCP to a USB hd ... it does an awful lot of head movements during copy ... I just copied a file using Samba, which was about 3-4x as fast, while I could hardly hear the drive doing anything. Doe the same thing with WinSCP, and the head seems to be moving dozens of times every single second ... and no, the drive isn't very fragmented, either ... (that's why I tried the Samba copy, too)

Seems to me WinSCP has some problems with its I/O handling ...

I hope this gets better with 4.2.x. If not let me know then.

VERY SLOW but nice GUI

had .3 to 2.5 MBs where copy from the commandline with SCP gets 8.5MBs

if you run wireshark you see why: many tiny packets, ACKs etc

think the problem is fragmentation: there are many 1400 odd size packets, immediately followed by another few hundred, and the latency then ruins high transfer rates

guess one would have to compensate for the "growth" of packets due to encryption - maybe with some change to the MTU generated by WINSCP (e.g. smaller size max 1300 byte?)

When connecting (or edit the saved session) use the SCP protocol. With it the transfer changed from 1.8 - 2.2Mb to 8.5 - 8.8Mb with 100Mb lan.

i can confirm this. tunnelier is "much" faster.

the question is, why?

currenly i am "forced" to use tunnelier but i would really like winscp to catch up, as tunnelier is bloated and lacks usability.

Just an update. I tried Tunnelier. Very impressed! And it ran at 8.5MB/s (on 100Mb ethernet), about 8.5x as fast as WinSCP was on the same Vista laptop.

Must say I've ALWAYS had this problem with WinSCP. it's about 10x slower than scp on the same hardware

I very rarely use windows, mainly guests that come to my house, and I want to copy large amounts of data across to their windows boxes.

Any suggestions? I'll try Tunnelier, but I really want LAN speeds like I get linux to linux (sustained 11MB/s using scp). i.e. I want the data to stream into windows at 10MB/s, not 1MB/s..

I haven't tried turning off SFTP, will try that next time a windows box walks into my living room, but

It's unfortunate, as WinSCP is a great bit of software apart from failing at this critical thing.

Sorry this is a bit more of a "me too" rant than a useful support request.

Craig

Hi,

i had the same problem. Using SCP is faster than using SFTP but now i use cygwin & openssh at command-line.
This is 3x faster than WinSCP with ssh-protocoll.
Something is slowing down WinSCP.

Maybe you find it someday.

Thank you! Works for me! Looks like SFTP is slow as turtle. Maximum speed is about 1.5Mb/s, no matter what CPU you have. After switching to SCP, transfer rate and CPU usage climbed up. After trying different encryption modes i got it running about 5.5Mb/s.

(As side note, Linux <-> Linux SCP transfers are much faster with same hardware)

So, can we expect a fix?

This speed difference is astonishing. But as Tunnelier can be downloaded for free the WinSCP autor should be able to verify the difference by himself now.

I must say that this difference is quite important, not only for big files. In many parts of the world internet is slooooow. FTP is just on the edge of being usable. If you turn to SFTP it becomes unusable (due to the added overhead and the many additional requests, it seems). That simple. Travel to some countries in Asia and you know what I mean. More timeouts than transfer. But when it doesn't work with WinSCP, it does work with Tunnelier. So this really should be fixed...

I too verified that there is a speed problem, transferring a file with size 74,319,711, was going to 2 to 3 minutes (local lan, gigabit network)
I installed bitvise tunnelier(as suggested earlier), wow....what a speed difference.

vista(32bit, sp1)
scp 4.0.7

After spending a decent amount of time trying to fix up Windows XP networking to run quicker I stumbled onto another program- Tunnelier. Transfer rates are MUCH quicker using Tunnelier rather than WinSCP.

Monitoring throughput on the TCP stack using 'Bandwidth Monitor' utility:
WinSCP sustains an average of 1.8mbps
Tunnelier sustains an average of 4mbps

If you compare the file transfer rates as reported inside each client:
WinSCP sustains an average of 160KiBps
Tunnelier sustains an average of 500kBps

Those tests are done using SFTP and no compression. It is trickier to compare once you turn on compression because the numbers bounce around too much in WinSCP- it does not do a good job of SMOOTHING out the average transfer rate that it displays.

The way WinSCP was pegging at 1.8mbps I thought something in the OS networking stack was preventing it from transferring quicker- but it must not be the case if another client can fly beyond that limit without any trouble. Also WinSCP was using Blowfish cipher (as recommended for better throughput). There was not any noticeable difference when switching between the different ciphers in Tunnelier (in fact in those tests Tunnelier was using AES-256).

Well I do like the WinSCP application a lot- which is why I wanted to share. Hopefully this will provide some motivation that the transfer rates need to be improved. WinSCP is just not fast enough when you need to do large transfers (I am talking about >100GB). In that case we are talking a DIFFERENCE of several DAYS).

-Steve

The slider has been replaced with input box in 4.1.

What is this speed slider? I have seen reference to it but have downloaded 4.1.2 (among other versions) and can't find it.

Thanks. What version of WinSCP are you using? Can you try 4.1 beta, if you do not use it already?

SFTP

What protocol are you using?

I had 6Gb to download and noticed the same thing, In the middle of the download I ran windows update and to my suprise while the update was running the transfer rate increased by 5 fold, when the update was finished the transfer rate went back to slow. I then ran some high CPU tasks and what do you know, the transfer went up each time the Task were running, and went back to slow when they finished.

This issue has been added to tracker.

Have you tried PSFTP or PSCP?

Sadly, for me, switching between SCP and SFTP makes absolutely no difference. It feels like a software cap, but obviously isn't. Nothing in the FAQ makes any difference.

Strangely, bringing the "5%-100%" slider down to 5% only cuts the performance in half.

I noticed it the other day and had to come back to finalize this post. For some reason WinSCP defaults to SFTP as the transfer protocol. I assumed it would use SCP by default due to the software's name .... switched it SCP now the speeds are excellent. I hope this post gets indexed into Google because the FAQ is not but another post without solution is.

Hope this helps somebody else.

BTW, instead of posting: "Please read FAQ first." You could have posted "Switch to SCP" would have been nicer and more helpful.

Please read FAQ first.

I'm only getting a transfer rate of 1500KB/s from my Linux server to my Windows computer. The windows computer is running Linux and Windows as dual boot, when I scp from Linux to Linux I get ~8MB/s transfer rate without compression enabled.
I checked WinSCP options and compression is off, I just downloaded the latest version 4.0.5 and it is the same problem.
I need to transfer 25GB from Linux to Windows and WinSCP estimates 4.3 hours, I can burn the files to DVD faster then that....

Any ideas on what is causing this?