Are you sure it is choked on writes not on reads and writes? SQLite default setup is inefficient in many ways (as well as it's default compilation options), and that often cause issues.
(I am just asking: are you sure WAL is on?)
I'd imagine that's it. With WAL you can probably hit >1000 writes a second
I'd imagine that's it. With WAL you can probably hit >1000 writes a second