FWIW, I had to cut some stucco, which is similar to cement board. A SawZall
made terrible jagged cuts, and pulled on the stucco making fractures that
looked like a giant cobweb. I got a SkilSaw with a metal cutting blade, set
the depth properly, and breezed right through it. I did have a helper with
a vacuum to help keep the dust down, but there was still a lot.

Steve