@HashBackupJim \- `newSeqOfCap[T](someLen)` also exists and, yes, pre-sizing can help a lot in Nim (and almost any lang that supports it).
Profile-guided-optimization at the gcc level can also help Nim run timings a lot..In this case 1.6x to 1.9x for various `gc` modes. [https://forum.nim-lang.org/t/6295](https://forum.nim-lang.org/t/6295) explains how. LTO also helps since most of the boost of PGO is probably from well chosen inlining. @sschwartzer \- not only string benchmarks...Interpreter start-up/etc. Anyway, this isn't a Python forum, and benchmarking "always depends". :-) :-) Someone else should reproduce my `--gc:arc` uses more memory than `gc:none` for the original str1.nim or one with a `main()` (or both). I think this kicking the tires has probably uncovered a real problem.
