This sale is for one rare 1991 MIPS R4000 CPU wafer manufactured by Performance Semiconductor. Performance built some of the fastest CPUs of their day and this one is no exception. These 64 bit CPUs were used by Silicon Graphics to build high performance workstation computers in the early 1990s.They were about as fast as fast got in the early nineties. The fully processed wafer has a mostly green tint depending on viewing angle and lighting spectrum. It is in excellent collectible condition. It's an awesome beauty too. One of the best looking CPUs I've ever seen. Photos were taken under ordinary white florescent room lighting. Die photo credit Pauli RautakorpiSee many other rare and beautiful tech collectibles in my store.Thanks for looking!