In 2004 I was working for Microsoft in the Xbox group, and a new console was being created. I got a copy of the detailed descriptions of the Xbox 360 CPU and I read it through multiple times and suddenly I’d learned enough to become the official CPU expert. That meant I started having regular meetings with the hardware engineers who were working with IBM on the CPU which gave me even more expertise on this CPU, which was critical in helping me discover a design flaw in one of its instructions, and in helping game developers master this finicky beast.
It was a lot of fun, and the work was appreciated, so a few months before the console shipped I got a present from the leadership of the project – an entire silicon wafer of Xbox 360 CPUs! That 30 cm disk of dice (I’ve always preferred “dice” as the plural form of CPU “die”) has been hanging on my home-office wall ever since. At its largest extent it has 23 complete CPUs horizontally and 20 vertically, but much fewer than 460 CPUs total due to the circular shape of the wafer. A lot of CPUs are partially or totally omitted because of that – I counted 356 complete CPUs on the wafer.
It looks cool, it creates beautiful rainbow diffraction effects, and the individual chips are big enough that you can see the key features of the CPU that occupied my career for five years.