Generally, no. But you should benchmark your own code.

In my experience, some code paths are better optimized by cl.exe, some by gcc. Overall difference is negligible though.

Of things I have benchmarked in the past 5 or so years GCC has not been beaten by GCC for any of my workloads or benchmarks. I do mostly things related to 3d graphics and are heavy on the CPU, but what little IO I have done follows this pattern too.

As near as I can tell msvc is strictly inferior except for windows community adoption than gcc/mingw. Of course, benchmark your workload, I could be doing something odd that you are not.

it's never been true in general but still happens sometimes.