Maybe something to spin on to. Try using a NetGear GA-302T (Giganet adapter) and then start for example, a bittorrent download or have it host a webserver. It'll fail miserably and die, so bad that anything past localhost will not work until you reboot.

This has been confirmed by NetGear that
simply states, (and offer no solution.)

<quote>
Dear Sir/Madam

The GA302T cannot support a large amount of simultaneous high-traffic connections that exist when using programs such as a bittorrent client.

Regards

William Stewart
Netgear Support
<end quote>

This was tested at even 10Mbit and the problem persists.

Imagine NetGear having a card that is both unstable and deliver less than a $2 ISA Network card. It worked flawlessly with an IBM Pro, 3Com 905b and a 3Com 920b so
there is no doubt about the NetGear card being the culprit.