Gaming WLAN Card Issues

[luke_c]

Built my first PC a few weeks ago, didn't get the WLAN card until a few days ago. Installed it all fine and connected to my wireless router (BT HomeHub v3) but the speed is inconsistent, and also seems to vary on what program I am using to download. With Usenet (SABnzbd) I get anywhere between 50Kbps and 16Mbps. With Steam I get around 700Kbps to 12Mbps.
The card is an Edimax EW-7722IN card. I get a consistent speed of around 18Mbps with my laptops integrated wlan card.
What could be the problem?

 

[Originality]

Could be the signal is being interfered by the computer case or the static field given off by the electronics inside.