Apple: Mountain Lion downloaded 3 million times in 4 days

By the end of the day Saturday, Apple(s AAPL) had tallied 3 million downloads of its latest desktop operating system, OS X Mountain Lion, which is easily the fastest uptake of any of its desktop OSes, ever. Mountain Lion was released to the public last Wednesday with a download price of $19.99.

“Just a year after the incredibly successful introduction of Lion, customers have downloaded Mountain Lion over three million times in just four days, making it our most successful release ever,” Apple SVP of Worldwide Marketing Philip Schiller said in a press release Monday.

There were hints by late last week it had been a very successful software release for Apple already. Chitika Insights released data it had gathered from its ad network showing that Mountain Lion was running on 3.2 percent of all Macs, just 48 hours after the OS became available.

That Apple is calling it the most successful Mac software release ever shows a couple of things. It  means Apple’s decision to forego physical software distribution, either via DVDs or USB drives, was smart: Mac App Store-only availability is driving faster adoption of the software. It also probably helps that Mountain Lion is a little bit cheaper than Lion, which cost $29.99.

But the fact that Mac customers are pouncing on its desktop OS also shows that even with Apple’s iPhone and iPad-centric vision, its traditional PC business is still very hot.