Network performance problem

[<trader@lotr.nu>]

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Hello,
         I am having some strange problems with my network. I have four
machines, Windows XP P2 450, FreeBSD 4.4 P200, OpenBSD 3.x P200 and a SPARC
Ultra 1 170 with Solaris 8 02/02. All machines run OpenSSH. Now when I
transfer files using sftp between them I get some really poor network
performace. Here are the sppeds in KiloBYTE not bit per sec between the
different verisions:

Upload to Solaris from Windows XP 65Kbyte/sec
Upload to Windows XP from Solaris approx 500Kbyte/sec.

Upload to FreeBSD from Windows XP approx 200-250Kbyte/sec
Upload from FreeBSD to WinXP approx 1000Kbyte/sec

Upload from WinXP to OpenBSD approx 130-170 Kbyte/sec
Upload from OpenBSD to WinXP approx 220-260 Kbyte/sec

Upload from OpenBSD to Solaris approx 650Kbytes/sec
Upload from Solaris to OpenBSD apparox 210Kbytes/sec

I have checked all the CPU usage stats and I never go above 80%. Most load
is when I am sending from the Unix systems (due mainly to their slower
CPU's). The OpenBSD machine had 80% CPU usage when sending, SPARC 75-79%,
FreeBSD same etc. None ever passed 40% when receiving. The machines are
connected to a seperate isolated LAN of their own and no traffic is
generated by other hosts. The test was run one host to another at a time.
Also all machines are set to 100Mbit full-duplex. I have tried changing NIC
from Netgear 311 to 3Com 905B's in the Intel machines. Any ideas what this
poor performance is caused by? I have checked with netstat and I have no
errors or col. Just seems to be VERY slow!!