Yes, but it's also useful to compare similar levels of effort. Using 4 threads with Snap is a similar level of effort to using thin. Setting up 4 separate processes with passenger requires quite a bit more effort, especially if you haven't done it before.

You can set up 4 processes with thin, just do:

> thin -e production -s 4 start

The problem is that each process listens on its own port. They can't all listen on port 3000, so you need some sort of proxy to parcel out the requests.