"Question: How much of a difference do "green" drives actually make in a system build? Do you save enough power for it to be worthwhile, or is it just a marketing gimmick? When a drive is "green," the designation usually just means that it runs on the slower side—5400 rotations per minute, as opposed to the more ubiquitous 7200 RPM. But in some cases, this slowdown can translate to drives that are quieter, cooler, and less power-hungry. We're not talking the same power savings as, say, switching to fluorescent light-bulbs from full-spectrum ones.