[strager]

Have you tried precompiling with -O2? IIRC runhaskell runs code like GHCi: interpreted bytecode by default (for source .hs files).

[payload]

Yes I have and I invite you to do it also by yourself to check it. There is no significant difference in this benchmark between "ghc -O2" and "runhaskell". I didn't investigated why... but I would be very interested in the details :)

Also "-threaded" gives the usual penalty of bookkeeping and bad caching and stuff. You don't need threads in such a benchmark. Though I am mildly surprised that "node" runs faster with multiple processes :)