> IME in incremental builds the most time is spent in the linker anyway. A lot of time is spent in the linker because the linker needs to parse and deduplicate

> IME in incremental builds the most time is spent in the linker anyway. A lot of time is spent in the linker because the linker needs to parse and deduplicate any monomorphized C++ classes (like vector). This takes time proportional to the number of compiled copies of the class / function that are kicking around. So I'd expect linking times to also decrease if you're compiling fewer, larger source files.