Windows 7 x64 Bit Wireless Internet

So I bought this kick ass desktop with a quad core 3.02 Intel Core i7 Processor. It has 9 gigs of RAM and blah blah great everything.

I bought a Linksys Wireless Adapter (WUSB54GC) to be exact, and it works with Windows 7 x64.

The problem I'm having is my internet speed. It's about half as fast as my macbook. My wireless internet connection just sucks on my computer. I have no idea why it's so slow. I'm thinking about downgrading to windows 7 x32

Any ideas why my wireless internet would be so slow on my computer?