winscp is 3-4 times slower than sftp/cygwin

Using the same machine as a client, I copied a file
from the same server using WinSCP and sftp on cygwin.

Sftp/cygwin almost maxed out the available bandwidth
of the narrowest section of the entire connection,
which is the upstream path of the ADSL circuit on
the server, which is 1Mbps.

Meanwhile WinSCP reports only 200-300Kbps on the same
physical connection.

This means if sftp took 1 hour to copy one file,
WinSCP would take 3-4 hours. That's a huge difference.

The server is openssh/cygwin.

What makes it run so slow?

I do not know. Unfortunatelly I do not have that fast connection to test it. With my slower connection WinSCP is as fast as SFTP.

What encryption are you using?

I found that changing the encryption preference to blowfish did wonders for my speed.

from ~700KBps to 2-3MBps.

Valheru wrote:

What encryption are you using?

I found that changing the encryption preference to blowfish did wonders for my speed.

from ~700KBps to 2-3MBps.

I use the default encryption (AES). What encryption does use your Cygwin SFTP?

martin wrote:

Valheru wrote:

What encryption are you using?

I found that changing the encryption preference to blowfish did wonders for my speed.

from ~700KBps to 2-3MBps.

I use the default encryption (AES). What encryption does use your Cygwin SFTP?

I don't know how to configure the encryption in sftp/cygwin.

Does this blowfish encryption work with a openssh/cygwin
server?

Okay, I tried blowfish on WinSCP and it was faster.
But not much. I would say 10 percent faster. I would
like something that's 3x or 4x faster, not 1.1x.

I learned that if you use sftp/cygwin without explicitly
specifying the encryption algorithm, then it would use
"3des", or Triple-DES. Blowfish is considered faster
than 3des.

Do make sure you are running winscp version that has PuTTY 0.54 or better; when I upgraded to 3.6.6 (from 2; don't remember the exact lvl), my sample 44MB file went from 2min11sec to 1min10sec. In my case, two systems on the same 100Mbs ethernet lan; both having 100Mbs ethernet cards.

I'm considering adding some "speed" page on WinSCP site, so people can compare their speed results.