I'm not sure, but I used to run the Nightly build on all of my Windows machines in order to use 64-bit Firefox and anecdotally Waterfox does "feel" quite a bit

I'm not sure, but I used to run the Nightly build on all of my Windows machines in order to use 64-bit Firefox and anecdotally Waterfox does "feel" quite a bit faster. I definitely notice fewer pauses.