This [pull request](https://github.com/nim-lang/Nim/pull/21798) improves the thread safety of ARC with surprisingly little overhead. For some CPUs. Please help us by joining our benchmarking efforts.
Please report: Stats for `koch boot -d:release --threads:on --mm:arc` Stats for `koch boot -d:release --threads:on --mm:atomicArc` Your CPU.
