>If you're targeting Windows, the default new operator / malloc is also comically slow. Luckily that one is fairly easy to fix with installing mimalloc and deploying the hijack dll, but the negative effects on cache by the fragmented allocations is also significant.

Surely nobody outside microsoft is doing serious work targeting Windows any more are they? Isn't that a dead platform? I read somewhere a while back they're now below 60% market share.