Now, we're not sure what Gigawire actually is, but we note that it is an Apple technology - at least, the Mac maker applied for the name as a registered trademark on 5 September. The trademark application doesn't describes Gigawire per se but it's clear it's some kind of cabling technology. A faster version of Firewire seems likely, indeed we've already been told that the new machines will ship with IEEE 1394b, which we've heard described separately as "Gigabit 1394". The official 1394b spec., finalised last May, provides for 800Mbps data throughput, rising to 1.6Gbps and even 3.2Gbps with optical cabling.
Our source chooses not to - or (s)he can't - provide more detailed specifications for the Power Mac G5s and their component technologies. Previous reports from the source have claimed the frontside bus is 400MHz and the chip contains 512KB of on-die L2 cache.