I would argue processors are never commodities anymore (maybe back in the 486 days it was closer). You can't swap an intel for an amd processor into the same motherboard ever today. They don't have the same performance characteristics from one to another. You could have 2 "3.5Ghz 4-core processors" that have wildly different real-world performance. IMO this is the opposite of "fungible"

I think hard drives, memory, power supplies are much closer to being fungible.