Remember that these are both Linux benchmarks; GCC on windows is a bit sketchy with MinGW. Things can usually be made to work, but Clang is the only real competitor to MSVC (unless you're counting Intel's crazy-expensive offering, which is not intended for general use).
https://www.phoronix.com/scan.php?page=article&item=gcc9-cla...
https://medium.com/@alitech_2017/gcc-vs-clang-llvm-an-in-dep...
Remember that these are both Linux benchmarks; GCC on windows is a bit sketchy with MinGW. Things can usually be made to work, but Clang is the only real competitor to MSVC (unless you're counting Intel's crazy-expensive offering, which is not intended for general use).