What baffles me is how slow this seems to be for everyone. I get some .7 seconds (plus or minus some random noise) for both Nim and Julia, both with clang, gcc-5, and gcc-7. Julia is a tick slower (around .78 seconds for Julia vs. .72 seconds for Nim), but nothing that breaks even the single second barrier. That's on a 2.5 GHz Core i7, a mid-2014 Mac, so how hardly a particularly powerful system.
This is with the code copied and pasted from the first post in this thread and no modifications applied.
