It’s faster in some ways and slower in others. But in general this is “very fast” vs. “very fast”. You won’t find yourself wanting in web service performance in either language, for example.
I wouldn't expect F# to be faster in anything actually, speaking as a .Net developer. OCaml is very well optimized and the abstract machine was well designed to have an efficient execution. Do you have any specific examples where the CLR is better?
Yes, you can find several benchmarks on the language benchmarks game, for example. And I would expect that any situation where you use Spans in F# to outperform almost everything outside of native code (just like with C#).
It's complex [1], OCaml does have a unboxed representation of floats in arrays [2] and records (provided all fields are floats), but elsewhere they are indeed boxed.
Good point. Polymorphic code that doesn't reduce to an unboxed float representation can be slower because of the boxing, but I don't think such code is very common exactly for this reason. I wonder if OCaml developers have tried NaN-boxing to see how it would impact performance.