If you own a Retina MacBook Pro, here’s a nice little perk to upgrading to OS X 10.8.3: you’ll get about 20 minutes more battery life per charge.
The Mac Observer ran the update through its paces and here’s what they found:
We decided to also run tests on our 2012 15-inch MacBook Pro with Retina Display (rMBP). We privately tested each beta build of 10.8.3 on both MacBooks as they were released and, starting with build 12D76, we saw a noticeable jump in battery life on the rMBP. Running time went from 398 minutes, which was roughly the same as the public release of 10.8.2, to 421 minutes, a change that persisted with the final build.
If you have any other MacBook, though, don’t hold your breath. The new update doesn’t improve much for non-Retina MBPs.
Source: Mac Observer