Go is using 1 CPU core with the max number of threads available on the OS. Where as C++ is using 8 threads. Go is using default complier compiler settings. C++ is using G++ at O3 optimization.

Overall, the ease of use of Go is much simpler as Go has built-in support for concurrency and parallelism. While, C++ needs the assistance of external dependencies like open MP. The other thing Go uses CPU cores and then threads it on each core available with the max amount of threads available making the comparison sort of unfair as Go is automatically using the best configuration for the solution. While, In C++ with open MP you have to specify how many to use externally. Go is jsut just much easier to use an implement a parallel/Concurrent solution than C++.