Just to dispel a common myth: in general, Ocaml cannot be as performant as C++ today. As far as I'm aware, no Ocaml compiler performs auto-vectorization of loop

Just to dispel a common myth: in general, Ocaml cannot be as performant as C++ today. As far as I'm aware, no Ocaml compiler performs auto-vectorization of loops, which means no SSE for you, leading to a 3-4x slowdown on last-generation CPUs and even more on future CPUs. Vectorization is a big deal if you want to maximize performance. I do agree, however, that this doesn't make C/C++ necessary for game programming. That's probably why modern game engines let you write a great deal of the game logic in a scripting language. Of course, most C++ code I see - even in language performance benchmarks - doesn't vectorize either. g++ isn't particularly good at it and most people don't know how to do it.