Is it more efficient to copy a vector by reserving and copying or by creating and swapping

Question

I'm attempting to efficiently duplicate a vector. I see two potential strategies:

std::vector<int> copyVecFast1(const std::vector<int>& original)
{
  std::vector<int> newVec;
  newVec.reserve(original.size());
  std::copy(original.begin(), original.end(), std::back_inserter(newVec));
  return newVec;
}

std::vector<int> copyVecFast2(std::vector<int>& original)
{
  std::vector<int> newVec;
  newVec.swap(original);
  return newVec;
}

What is the preferred option, and why? 

I'm trying to find the best approach that won't require extra copying.