In his lengthy and ultra-detailed review of Mavericks, John Siracusa of Ars Technica conducts battery benchmark tests to measure Mavericks‘ power saving features on both a 2007 MacBook Pro and a 2013 13.3-inch MacBook Air.
While both systems saw notable battery gains going from Mountain Lion to Mavericks, the 2013 MacBook Air in particular saw impressive improvements of up to 30 percent, lasting for more than 15 hours in some instances.
For his battery tests, which were conducted using OS X 10.8.5 and the GM build of Mavericks, Siracusa created a light Web browsing and text-editing automation script, including websites that used Flash. In his tests, battery life varied significantly, but provided, on average, an increase of two hours of work time.
I suspect the aggressiveness of the auto-playing Flash ads that happen to be on specific websites on a particular day may partly explain the huge variability in Mountain Lion’s numbers. Some of the lower-scoring Mountain Lion trials may have also had the bad luck to coincide with energy-intensive periodic jobs—jobs that are prevented from running on Mavericks due to AC power or battery-level restrictions as part of centralized task scheduling.
These tests may or may not be representative of how you use your Mac, but regardless, it’s clear that Apple’s efforts have not been in vain. Mavericks really does consume less energy than Mountain Lion when performing the same tasks.