A large number of MacBook Air, MacBook Pro, and Retina MacBook Pro owners have been reporting significant decrease in battery life after upgrading to Mountain Lion, Apple’s latest OS X iteration. Some users have even experienced almost half the amount of battery time on Mountain Lion as compared to OS X Lion. Looking into the matter, Ars Technica has performed extensive tests on a Retina MacBook Pro confirming that some bit of software within Mountain Lion indeed appears to noticeably reduce battery life for MacBooks.
Detailing from the source:
Following on numerous reports lodged in Apple’s support forums, we did some additional testing using our Retina MacBook Pro review unit, which seemed to lose approximately 38 percent of its previous 8-hour runtime after installing Mountain Lion. Apple support technicians are continuing to gather evidence from users reporting problems, though at least one user has been told that an update from the Mac App Store should address the issue.
Our own testing revealed similar (and significant) drops in battery runtime after installing Mountain Lion. In previous tests, we were able to regularly achieve just over 8 hours of use by relying solely on our Retina MacBook Pro’s integrated Intel HD4000 GPU. Performing the same “real-world” test using the same software applications and usage pattern, we never got the Retina MacBook Pro to run for more than a few minutes past 5 hours after a full charge.
Apple was not able to confirm to Ars that a fix was forthcoming. However, they have forwarded their testing information to the Apple’s software team for review.