I'm pretty sure that USB is slower than ethernet on a cable modem. I could test the theory, since my cable modem supports both. I'll do it after my run this morning and post the results.
Theoretically, you shouldn't notice a difference since both USB and Ethernet transmission speeds are way faster than your cable modem connection. You may notice a difference due to the implementation of each on your product and the drivers on your machine. I know in the past, most people stayed away from USB because the implementation was buggy as hell especially on VIA chipset-based PC's.
With the high speeds you guys seem to get with Time Warner Road Runner, I'm pretty upset with my 50kbps now... Road Runner is messing with my mind!
I went from dial up on a 350 mhz p 2... to 5.319 Mbps (680.89 KBps) on a p4 2.4 ghz machine... so this is such a huge upgrade for me.. ah i love this college network! Is this fast for a college network or about average.. . I think some people at UT were saying it was considerably slower there?