openssh unix dev - Mar 2006 - Cygwin sftp is very slow.

I tried to transfer a CD image (around 600Mb ) from a local network linux
machine to a windows machine with the cygwin sftp. The transfer is very
slow. It did not go beyond 15KB/s But I did transfer it just with ssh and it
was pretty quick.

ssh logu at 192.168.1.52 "cat sysrec.iso" > sysrec.iso

What could be the problem. I have switched off Antivirus, firewall etc.

The version of the cygwin openssh client is:

$ ssh -V
OpenSSH_3.9p1, OpenSSL 0.9.7d 17 Mar 2004

Any help will be appreciated.

Thanks
-logu