A new set of tests published Sept.10 showed that MacBook battery life increased significantly with a developer build of OS X Mountain Lion, with the recent beta version enabling an 85-minute increase from current 10.8.1, AppleInsider reported.

The report gains significance as previous reports from Ars Technica noted the decrease in battery life of notebooks as a major issue while upgrading from OS X Lion to OS X Mountain Lion. Ars Technica noted a 38 percent decrease in battery life following the upgrade.

A study conducted by Mac Observer notes that the second version of Mountain Lion OS X 10.8.2, also the current beta version that is well into testing, completely restores battery life of notebook to OS X Lion levels. This resulted in approximately 380 minutes of power under testing protocol, compared to 260-275 minutes under OS 10.8 and 280-300 minutes under OS X 10.8.1, MacRumors has reported.

Quoting Mac Observer's study results, a statement on MacRumors read: "Just as we saw in our previous tests, the upgrade to 10.8 Mountain Lion decreased battery life significantly, by about 1 hour and 45 minutes, or 30 percent. The upgrade to 10.8.1 restored about 30 minutes of battery life for our MacBook Pro, an improvement for sure, but not nearly enough to regain lost ground."

"The big change came with 10.8.2, which is still undergoing developer testing. Using the latest build, 12C35, we saw a tremendous increase in battery life, to the point where running time was a few minutes longer than even that of 10.6.8."

It is to be noted that not all notebook users have experienced significant battery life reductions with OS X Mountain Lion and it is unclear what the root cause of the issue is, Mac Rumors has noted, adding that OS X 10.8.2 may resolve all battery life issues on the impacted notebooks.

Earlier, too, batter life of notebooks became a discussed topic after the introduction of OS X Lion, which was apparently resolved with the release of OS X 10.7.3, six months after the debut of OS X Lion, Mac Rumors stated.

Mountain Lion Adoption Crosses 10 Percent After First Month

In another related development, Chitika Insights, the research arm of ad firm Chitika that monitors and analyzes web traffic across its network, noted that Mountain Lion usage constituted 10.3 percent of all Mac-based desktop impressions.

This was significant as it seemed to be on track to outperform predecessor OS X Lion, which had taken three months to reach 14% of total Mac OS X traffic, Chitika stated.