When the packet driver installs, what MAC address does it report? Does it seem like a reasonable MAC address for the card? If the MAC address is wrong that is a sign that the packet driver is not actually talking to the Ethernet card. I would not expect that on a PCI Ethernet card, but who knows.

Second, do any of the mTCP programs ever report seeing a packet being received? On most networks there is enough broadcast traffic going around, so mTCP should detect something coming in from the packet driver. You can ping an unused address on your local network to generate some extra ARP traffic that will be seen. If you never ever see a packet being received that is a sign that the hardware interrupt being used on the card does not match what the packet driver is using.

Gigabit is overrated. The packet driver specification is so horribly inefficient that it won't matter. 100Mb/sec is fine, but I suspect that gigabit is wasted if you are using packet driver based software. Packet drivers do *two* calls to the application for each packet received. There is no scatter/gather available. There is no TCP offloading available. It was good back 20 years ago, but Ethernet is 100x faster and the cards are far more powerful than they were back then.

Both Linux and netbind show the same MAC address so I'm assuming that's all working correctly.
mTCP's DHCP Program says that no packets were seen on the wire, the interrupts appear to be set correctly too.

For most things I'd agree that gigabit isn't worth the hassle, except in my case it cut the load time on my Win98 image in half.
Though it's pretty worthless if I can't sync the ramdisk because I can't use the NIC.

Edit:
I went gigabit for diskless booting of XP and Linux mainly, though I never bothered to research beforehand if it would make any real impact.
Hmm...