The network card doesn’t run as fast as advertised

Click Start, Control Panel, and Switch To Classic View, and double-click Network Connections. Right-click Local Area Connection, click Properties, and click Configure. Select the Advanced tab and click the speed-related entry in the Property box. Use the Value drop-down box to select the fastest speed your network card supports, which is likely 10/100Mbps Full Duplex but may be 1,000Mbps Full Duplex if you have a Gigabit Ethernet card installed.

Click OK and reboot the computer. The card should operate at its full speed, assuming your router and the network computer you’re connecting to also support that speed.

The speed of a wireless NIC depends mainly on the strength of the wireless signal it receives. You can get a quick read of the strength of your NIC’s wireless connection by hovering the mouse cursor over the wireless icon in the system tray and waiting for a balloon to appear that tells you the overall signal strength. If it doesn’t say Excellent or Very Good, then you may need to move the computer closer to the wireless router, upgrade the router, or invest in an antenna that attaches to the router and boosts the signal.