And with the author's hot off the presses nim flags I get only 1464 fps. So, 1920/1464 = 1.31 for my nim compile flags vs. his new ones, only a little less than the 2521/1626 that was interesting people.

For something super jumpy like a simulator, I would find it unsurprising for PGO to make up (or surpass) the difference to Zig in both Nim and C++. 20 years ago there was this ACOVEA [1] project to try to discover great sets of gcc flags that could often find 2X improvements in object code speed for me.

The range from build flags/procedures is often much greater than the supposedly interesting cross-language variation. These things often more measure developer experience/persistence than something intrinsic (and build flags/procedures are only part of that experience/persistence).

[1] https://github.com/Acovea/libacovea