SSH Overhead

I have an brutto upload bandwidth of 447 kbit/s (=about 55kbyte/s).
WinSCP uploads only with an average of 21 kbyte/s. No other services are using the upload.
Is this due to ssh protocol overhead?
If not, what upload rate would be normal?

Thank you!

Not because of SSH overhead (although partially too), but rather due to SSH and SFTP windowing mechanism that prevents utilising full bandwidth. And of course there is still lots to improve in the WinSCP itself.

Are there any possibilities to improve the speed? I have to transfer rather large amounts of data like 6GB every week...
Do other SSH clients like putty have the same issue?

Thank you!

maniac wrote:

Are there any possibilities to improve the speed? I have to transfer rather large amounts of data like 6GB every week...
Do other SSH clients like putty have the same issue?

WinSCP is based on putty. There were some improvements in speed in the last putty version, so maybe after an upgrade of code.

Thank you!