A lot of military silicon is, in microarchitectural terms, very old. People overestimate how much CPU is required. For example, reliable hypersonic kinetic inte

A lot of military silicon is, in microarchitectural terms, very old. People overestimate how much CPU is required. For example, reliable hypersonic kinetic intercept of hypersonic targets (i.e. the proverbial bullet shooting down another bullet, where both are hypersonic) can be, and has been, done all day with a MIPS R3000 CPU. The physical limits of materials restrict systems to much lower reaction times than even ancient CPUs are capable of. The advantage of old CPUs is that you can harden the hell out of them and be made to have very predictable properties. Also, the CPUs tend to be for orchestration and control. If you need any kind of heavy exotic processing, there is a dedicated piece of silicon for that purpose. Complex US weapon systems like the F35 are a mixture of silicon that was old before some people here were born and state-of-the-art beyond what is available in commodity systems. They generally use the oldest most reliable tech that won’t compromise requirements for any particular use case.