I built a new PC and have been using a USB wireless adapter for internet access since my router/modem is in a different room. I have 12Mbps service. speedtest.net shows 6-12Mbps for the laptop but the PC never gets above 4.6Mbps. I've tried two USB wireless adapters. Both work fine in the laptop but I always get the slower speeds on the PC.
PC is spyware free and less than a month old.
PC stats: Windows 7 Ultimate 6 core CPU 8GB RAM USB Wireless adapter: TP-Link TL-WN321G (54Mbps). At first I was only getting about 1.5Mbps and then I installed the Win7 drivers from the TP-Link website and that's when I started getting 2-4.6Mbps.