C++ STL

Is it faster to iterate through stl vector with the [] operator or an iterator?
I would think that the iterator is faster but I'm too lazy to test.

>>5 is the winner^[1]

References:
1. http://www.cplusplus.com/reference/stl/vector/
   "Accessing individual elements by their position index (constant time)."
   "Iterating over the elements in any order (linear time)."