Concept of connection between the PC and the cable modem
Even if downstream channel works at 27 Mbps, user interface is nearly always 10-Mbps Ethernet. There is no way to get bits to computer any faster than 10-Mbps under these conditions. If connection between the PC and the cable modem is fast Ethernet, then full 27 Mbps can be available. Usually, the cable operators specify 10 Mbps Ethernet sincethey do not want one user sucking up entire bandwidth.