Network card problems, please read :)

[xplosiv]

I finally got gentoo up and running, and I am having problems with 1 of my 3 network cards. Ironically, it's also the card that is the most important to me since it's a quad ethernet card. I have network connectivity (mii-tool confirms this), when I ping, everything seems to be normal, but when I try transferring larger amounts of data such as a download (either using Wget or sftp), it seems to die before the file reaches 1 meg (it doesn't always die around the same size though). Restarting the transfer sometimes works, but in many cases it just sits there.

If I plug the network cable back into my other network card, and configure that card with the same ip address, and bring the interface online, I do not have this problem. I recompiled the kernel many times, disabled ACPI etc, but no matter what I do, I can not get around this problem. I seem to have the same problem with the live CD, so I don't think it's my kernel configuration, unless both have the same wrong options set.

This machine was going to be my new firewall, and this problem is a real showstopper, and I am out of ideas. Is there anything else I can check to see if i.e. IRQ's are conflicting or other resource issues? Any help would be greatly appreciated! Thanks guys.