So me finishing a carded up block of work that is expected to take 2 weeks (80 hours) and I get it done in 1 day (8 hours) then that would be a 10x boost.
There are always tar pits of time where you are no better off with AI, but sometimes it's 20x.
I've setup development teams in the past, and have have been coding since the late 70's, so I am sort of aware of my capabilities.
It super depends on the type of work you're doing.