I've been working both with Clang and MSVC nearly daily for the last 10 years. My impression during that whole time is that MSVC (on Windows) is universally slower than Clang (on Linux or macOS, Clang on Windows is also not exactly a performance wonder though).

Clang might have become slower over time, but it still has a long way to go until it gets down to MSVC's average performance.

Only if you aren't using pre-compiled headers, or hot code reloading, alongside incremental compilation and linking.