Pedantic comment: you don&#x27;t need the previous results to compute the nth fibonacci number; the recurrence has a closed form solution. It is not constant time to compute (unless you assume constant time, infinite precision arithmetic) in practice, but it can certainly be done without the prior terms.<p>The rest of this post is on point, though. Serialization bottlenecks (Amdahl&#x27;s Law) prevent a lot of optimizations from making meaningful dents in real workloads.