Tekserve, which bills itself as "New York's largest independent Apple store," timed the Mountain Lion upgrades it installed on various Mac desktops and notebooks, averaged the scores for each model, and posted the results on its Wednesday.

first reported on Tekserve's time trials.

Earlier today, from its e-mart, the Mac App Store. Mountain Lion costs $19.99, and can be installed on most recent Macs running either OS X Lion or Snow Leopard.

"Unsurprisingly, the new [Retina] MacBook Pro was far and away the fastest to update, with the new MacBook Air models close behind," said Tekserve, which is located on West 23rd Street in Manhattan. "Their speed can be attributed to having solid state drives [SSD], which can access data much faster than a standard magnetic hard drive."

The Retina MacBook Pro, the 15-in. notebook with a higher resolution screen that unveiled last month, completed the Mountain Lion upgrade in just 13 minutes, while the 11-in. and 13-in. MacBook Airs needed 17 minutes.