Computer system 100 includes at least one CPU 102, system memory 104, memory and I/O controller 106, and several I/O devices 108 such as a printer, scanner, network interface or the like. (A keyboard and mouse would also usually be present as I/O devices, but may have their own types of interfaces to computer system 100.) Typically, memory and I/O controller 106 will include a system bus 110 and a