I just switched over from a 3.0 MBPS DSL to 15.0 MBPS Internet thru cable, using a cable modem plugged into my airport express. I have tried downloads on both computers. Trying to download a video from iTunes that I previously purchased will give me a rate of about 900 kb/s on one MacBook, but the same movie on a newer MacBook Pro will only give me a rate of about 280 kb/s (same as the speed it got on DSL). Is it possible that the Express is limiting high-speed bandwidth to the 1 MacBook (is the one with the lowest IP Address, and the computer I used to initially setup the Express)? The Fast MB is running Lion, and slow MBP is on Mountain Lion. Any thoughts? I have ran speedtest.net on both, and they each show about 18.8 MBPS connection on download, but when it comes to downloading files, the older MB is almost 4x faster than the newer MBP, even when downloading same file.