Update: Download links are now live! Click here to grab OS X 10.9 Mavericks from the App Store.

Apple kicked off today's media event going over the tenth release in the history of OSX. Dubbed Mavericks, the newest version of Apple's operating system focuses on three core areas: technologies, features and apps. The company already walked us through a few of the improvements back in June during WWDC.

Among the features highlighted today were Mavericks' power efficiency enhancements, which will reportedly allow up to an hour longer web browsing and 90 minutes longer video playback on the latest MacBook Air. Another new feature called Compress Memory can instantly compress inactive parts of memory to free it up for other applications, and fit 6GB of data in 4GB of RAM.

On the graphics front Apple has taken special focus on integrated GPUs with dynamic allocation of memory depending on load, as well as support for OpenCL so that the integrated graphics processor can take tasks that the CPU would normally handle and help them run up to 1.8 times faster.

That covered the technology part of the presentation. As for new features and apps, a quick demo by Apple's senior vice president of Software Engineering Craig Federighi went over shared links in Safari, enhanced notifications, Finder tags, better multiple display handling, the new Maps app and iBooks.

Apple says the new OS carries over 200 new features overall and though many of them have been detailed already, the company saved one big surprise for today: OS X Mavericks will be available today, for free.

This is the first time Apple has distributed a major update like Mavericks without charging. Its predecessor, 10.8 Mountain Lion was already pretty cheap at $19.99, while 10.7 Lion was $29.99. Today's update is not only free on the App Store but also available to anyone running OS X all the way down to 2009's 10.6 Snow Leopard.