Speeding up image builds?

I often find myself waiting for image builds to run. What are some steps I can take to make them faster? Generally, I find that image builds are I/O bound (CPU usage remains quite low), so one option would be to use a machine with better I/O. What is the best option for this? Is this something where thin provisioning (instead of thick provisioning) causes a large performance penalty? Or is the only solution to throw hardware at the problem? If the latter, what would better hardware be? -- Sincerely, Demi Marie Obenour (she/her/hers)