According to my network-brained friend tcp/ip packets of size less than 1KB will cause the downstream to slow down with the 10Mb:384Kbit ratio due to the ACKs that need to be sent upstream.
Though, I don't know what my average packet sizes are..
From
http://tinyurl.com/dsq3c average packet size seems to be about 620 bytes.. which means that we may not achieve full 10Mbit speeds..
And that's presuming that we do no uploading at all!