which is faster for-loop or foreach?

Question

Let on an array,

Method 1:

var array = ["a","a","a","a","a"];
  for(var i=1; i<=array.length; i++)
      array[i-1] += i;
  console.log(array);

Method 2:

  var array = ["a","a","a","a","a"];
  var i = 1;
  array.forEach(function(){
      array[i-1] += i;
      i++;
   });
   console.log(array);

Both methods on array yields same result, that is:

["a1","a2","a3","a4","a5"]

But
1) which is the fastest method?
2) Is there any other faster way to do the same thing that is convert ["a","a","a","a","a"] to ["a1","a2","a3","a4","a5"]?
3) Is there a way to know time taken by both code snippet? Please don't be too technical...