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...where Apple beats three community-developed libraries.That's just in one very restricted area (JSON parsing) where there are TONS of third-party libraries of varying quality for the exact same thing. Doesn't mean much in the big picture.
>I'm also skeptical because I don't see how Apple has any incentive to optimise code ever.
And yet, they use to do it all the time in OS X, replacing bad performing components with better ones. From 10.1 on, each release actually had better performance on the SAME hardware, until Snow Leopard at least. They had hit a plateau there I guess where all the low hanging fruit optimisations were already made.
Still, it makes sense to optimise severely, if not for anything else to boast better battery life.