Why is AddRange faster than using a foreach loop?

Question

var fillData = new List();
for (var i = 0; i < 100000; i++)
     fillData.Add(i);

var stopwatch1 = new Stopwatch();
stopwatch1.Start();

var autoFill          


        

Answer 1

i suppose this is the result of optimisation of memory allocation. for AddRange memory allocates only once, and while foreach on each iteration reallocation is done.

also may be there are some optimisations in AddRange implementation (memcpy for example)