> Processors from Intel and AMD may need updates to their microcode to operate correctly. These updates fix bugs/errata that can cause anything from incorrect processing, to code and data corruption, and system lockups.
Oh, there's still plenty of things beneath that level that can go wrong. Just look at Intel disabling HTM (through microcode, admittedly, but disabling a whole feature isn't fixing it to operate correctly) in Haswell/early Broadwell.
I don't think that's as big of an issue with modern processors:
https://wiki.debian.org/Microcode:
> Processors from Intel and AMD may need updates to their microcode to operate correctly. These updates fix bugs/errata that can cause anything from incorrect processing, to code and data corruption, and system lockups.