Unfortunately the std module alone doesn't help much because 1 second is 3x slower than before the optimization described in the post but maybe more fine-grained modules will (or if std module import made faster).
Also Microsof Office team has been migrating to modules, with great build improvements.
https://devblogs.microsoft.com/cppblog/integrating-c-header-...
Key takeway
"Fortunately, we were able to show a build performance improvement great enough that the team agreed to adopt header units into the Office production build system alongside msvc 17.6.6!"
Unfortunely the performance findings blogpost is still WIP.