I amusing a USB to connect my cable modem.
Ok, so why wonder about it?
I heard ethernet is 'better'.
Yep.
Is there any truth in this?
Yep. A little.
I mean in a 'blind test' could could someone say
"hmmmm this is obviously a USB connection, you should use Ethernet"
The issues are that USB is a slower interface, ties up the
system for longer per each transaction. USB shares
bandwidth with the other USB port of the pair. USB adds
another layer of complexity which is unnecessary (unless of
course, you NEED it to be USB).
It will work though, and some systems' USB is better than
others. You might find it results in slightly lower gaming
framerates if playing online, but my recollection of this is
vague, I have no solid data about it.
More importantly, you should not connect a windows system to
a cable modem. There should be a router inbetween because
windows is inherantly insecure (though through a lot of
effect you can improve this, but so much more if you do it
AND add a router), then if you want to use USB out of your
system to connect, you'd use a USB NIC to the router, or of
course the PCI or onboard NIC.
