Question : Why Am I Only Getting 100Mbps On A Gigabit Switch?

I have 2 PCs, both have GigE onboard NIC connected to each other though a 3Com 3CGSU05 Gigabit switch, and Cat. 6 cable length approx 30M.

Now one PC running XP SP3 could detect and run at 1.0Gbps flawlessly, assuming the network is fine. But the other one running Vista SP1 with a RTL8169/8100 onboard NIC could only detect 100Mbit, I tried to download the latest driver from Realtek but it didn't help.

I 've done some search and found maybe forcing it to run at Gigabit would work, but I don't know how to do that.

Any help appreciated!

Answer : Why Am I Only Getting 100Mbps On A Gigabit Switch?

Go into your network connection (can get there from control panel, networking...).  Choose Properties.

On General tab at top there is a Connect Using box that shows your network card.  Click the Configure button.    On the Advanced Tab you will find the settings.  Mostly it is called Link Speed and Duplex.  It's probably set to Auto Detect.  You can set speed and duplex manually here.

Lastly, you might check your switch configuration, some switches allow you to force a port to be a specific speed (not auto detect).  If changing the network card setting does not work then plug in to a different switch port or check switch configuration too.