I have a desktop and a laptop in the same room, about 30 feet from my router. The internet speed on the laptop is great, and on the desktop is horrible. I ran speedtest.net on both and this is what i got:
I thought maybe something is wrong with my Linksys WiFi card, so I tried using a Belkin USB Wireless adapter F9L1001 on the desktop and got the same result. Also, the drivers all hardware are up to date.