The % x86 column refers to the speed of a language on ARM as a percentage of its speed on x86. So if an implementation's % x86 is 50%, then it runs at half the speed on ARM as it does on x86. The versions of the languages/compilers used are in the 'versions' file in this repo. F#, Haskell, Rust and Dart send their apologies. F# didn't have an Arch Linux package for ARM, and when I built it myself