What occurred to AMD then, and which was a radical and dangerous idea, was that everything about PCs' total system architecture was wrong. The notion of a unified bus was discarded in favor of multiple independent buses driven not by external chips, but by the processors themselves. Simple, quiet HyperTransport replaced messy parallel buses. No Opteron server is recognizable as a PC, but AMD's obsessive adherence to an optional, well-publicized extension of the x86 ISA (Instruction Set Architecture) leaves software happily ignorant of its dramatically remodeled surroundings.
This topic came to mind while I was setting up a four-socket (4P), quad-core Shanghai Opteron system for testing with Windows Server 2008. The server astounds me. I delight in the incongruity of running a 16-way server on the power of a four-way workstation, and the fact that support for such a new design is already baked into a retail Windows release. The server fans roar at power up, as all 4P systems' fans do, but once it boots, active power management spins the fans down to a hush that is inaudible through the door of my GizMac XRackPro. That's a first for a top-end 4P machine. The server's BIOS has the speed and voltage tweakability (I'm an underclocker) of an enthusiast PC.
There is so much in this Shanghai server that's new, and yet the machine is as familiar to me as every Opteron server I've laid hands on since the original. As a technologist, it's exciting, in a way, to explore a design overhauled by necessity -- looking for improvements, finding the switches that enable them, and doing generational comparisons. As an IT person, it's more satisfying to plug a new Opteron server in next to its predecessor and note nothing but that it's faster and quieter. And to know that if the need arises, I can swap parts, even CPUs, among servers to maintain and reapportion my server assets. That's exactly how AMD set it up, and that's the approach I prefer.