M3 vs M2: M3 wins on battery, but only if you never plug in

The M3 gives you maybe 30-60 extra minutes of battery under light office work, but Apple rates both at 15 hours wireless web. The M3’s efficiency core is faster and uses less power for tasks like Safari and Slack, so it sips power more gracefully. If you plug in at lunch or dock at your desk, the difference is academic — the real battery killer in either is display brightness, not the CPU.