Shared mutated memory isn't necessarily a problem, because it still is unknown how often access is required to that memory.
E.g. having a thread that spends perhaps 1% of the time with state mutation vs 10 threads spending each 3% of the time with state mutation.
You have smaller efficiency per thread, but still higher efficiency overal
E.g. having a thread that spends perhaps 1% of the time with state mutation vs 10 threads spending each 3% of the time with state mutation. You have smaller efficiency per thread, but still higher efficiency overal