I have the Intel 82566DC Gigabit NIC on the motherboard of my TriCaster Studio. The system is running Windows XP Professional. When booting up, the network switch indicates the NIC is communicating at 1Gbs. However, when Windows XP Professional gets about 1/2 the way through boot up (usually right before the user login screen comes up), the speed drops back to 100Mbs. If I disable and enable the NIC from the device manager, it will show 1Gbs on the switch and 1Gbs in the icon tray or status window for about 6 seconds before it reverts back to 100Mbs. I have tried updating to the latest drivers, Forced Master from the Advanced tab,
However, when I boot into Safe Mode, without networking, the switch reports that the NIC is communicating at 1Gbs. Booting into Safe Mode with Networking causes the NIC to start out at 1Gbs, then drop to 100Mbs.
I appears to me that some driver is loading and causes the speed drop. Anyone have any ideas besides going out and buying a PCI NIC?
Update 6/9/2011: After a lot of searching and testing, I decided to purchase a PCI gigabit ethernet card for $14. I disabled the one on the motherboard. The system communicates fine at gigabit speeds with my other PC's. Either the driver has problems or the card just does not work with the motherboard. So, since my problem has been solved by installing a $14 card, I will close this discussion/question.
Disable this NIC and install a real functioning gigabit PCI card for $14.