Looking at the github it seems you benchmark GCC 4.8.1 vs. go 1.2rc1. Numbers for Go look promising if one considers that Google's Go implementation does not even have an advanced optimizer yet (in contrast to GCC).
Have you tried -O2? -O3 often generates slower code.
>i7 2600
Intel's compiler would probably generate faster code. That's why you can't just say "Go vs C++". You could let Go win this fight by compiling the C++ with Digital Mars. It is also a C++ compiler but it lacks a modern optimizer and the generated code is usually much slower.
>c++ -std=c++11 -O3 -Wall -pthread -ffast-math -mtune=native -march=native -o cpprays cpprays/main.cpp
Have you tried -O2? -O3 often generates slower code.
>i7 2600
Intel's compiler would probably generate faster code. That's why you can't just say "Go vs C++". You could let Go win this fight by compiling the C++ with Digital Mars. It is also a C++ compiler but it lacks a modern optimizer and the generated code is usually much slower.