I thought that F# was meant to be faster than C#, I made a probably bad benchmark tool and C# got 16239ms while F# did way worse at 49583ms. Could somebody explain why this is? I'm considering leaving F# and going back to C#. Is it possible to get the...

## Why in .Net HashHelpers.IsPrime is implemented in this way?

Looking at .NET System.Collections.Generic.Dictionary<T,T> implementation I found a method HashHelpers.IsPrime(n) which check if number is prime or not. I was confused a little bit why they use very simple optimization technique testing only odd numbers starting from 3.