Attempting to run that test on my computer caused everything to come to a complete standstill. It might have something to do with compiling it with g++/MinGW, though. And my system is fairly beefy, too.
In any case, I got negligible difference between the two, when you average it out. The interesting thing was the function pointer always seemed to be faster, which is not something I would have expected. Again, perhaps it has something to do with MinGW.