Slow file transfer between 2 computers

[videobruce]

If I transfer files from box A to box B using box A as the controlling terminal all is fine, BUT if I transfer the SAME files from the same location to the same location using box B as the controlling terminal the transfer is either very, very slow or dies altogether. I tried different files and the same thing. I reversed the transfer (B to A) and still the same thing. The computer which I used to initate the xfer shows no problem. If I do it from the other the xfer dies.

I have defragged both drives and changed NIC's in both boxes. I also forced 100 full duplex on both cards.
Both boxes are running 2k w/sp4 with new O/S installs.

Hope that made sense. Any ideas?

[Kunta Kinte]

What are you using to transfer? USB, fire wire?

[videobruce]

changed NIC's in both boxes

ethernet cards.