You are supposed to be able to get a gigabit connection. The only driver for that adapter is the one that comes with Windows, so upgrading the driver is not an option.
What is the brand & model of the switch? Does the switch let you configure the ports? Is there a firmware upgrade available for the switch you can try?
Thanks for the response! The switch is a Cisco Gigabit Ethernet switch. It is a "dumb" 24-port swtich, about 4-5 years old, and has no management capability. You've given me an idea though, I have 3 or 4 more gigabit switches in the house that I can use for testing purposes, so I will connect the Windows 7 box to one of those and see what happens.
Were you able to resolve this issue..?
I have a similar problem with a 1000 MT Dual Port adapter and ESXi
If I put the cable in one of the ports, I get a GB connection if I put the same cable into the other port I only get a 100 MB connection!? The card is connected to a Dell Powerconnect 2716 switch. I've also tried connecting it to a simple 3com GB OfficeConnect switch which also didn't help...