Went ahead, downloaded a 200MB installer, launched the thing. Didn't feel like 50ms at all.
Pulled out Superluminal of course, because Superluminal never lies. Turns out it's ~500ms, not 50ms.
From RtlUserThreadStart to the first ZwUserShowWindow: 476ms.
we do care, and our window is up in 50ms. bottlenecks exist elsewhere, they will be taken care of soon