Based pretty much on the same design as the OS X Yosemite, which originally brought the redesign which Apple moved to iOS 7, the OS X El Capitan will be rather focusing on improvements to user experience and performance, rather than design.

The biggest improvement in OS X El Capitan, is the new Spotlight Search, same one that Apple will be bringing to iOS 9, which was joined with Siri. While Spotlight Search was a big part of OS X and even gained an ability to search for keywords and phrases inside files with OS X Yosemite, it is now getting the same functionality of Siri to text searches with Spotlight. During the event, Spotlight was used to find a set of keynote slides about a natural park sent by certain person.

The Mission Control in OS X also got improved with few interface changes and an ability to drag windows into the bar at the top in order to put them in fullscreen mode. Apple also updated and improved the multitasking experience where you now have a feature that is quite similar to Aero Snap on Windows, allowing you to split the screen down the middle between two apps and more.

Apple also updated existing applications including Notes, Mail and Safari, where you can embed photos to Notes, or use trackpad gestures in Mail or slide tabs to the left to pin them in Safari.

The biggest focus with OS X El Capitan is on performance. With the redesign that came with OS X Yosemite, it was quite obvious that both CPU and GPU were under heavy load. Both the raw speed of the OS and the frame rate of animations have been something that Apple is focused on with OS X El Capitan.

In order to provide as much performance as possible, OS X El Capitan will be switching to Metal API, a low-overhead API seen earlier on iOS, or a new graphics core technology which gives games and apps near-direct access to the GPU, providing up to 50 percent improvement, according to Apple. The new OS X El Capitan will bring up to 10 times more draw-call performance for games, 1.4 times faster app launch, two times faster app switching and faster display of first mail messages as well as four times faster PDF opening in preview, at least according to Apple.

The new Apple OS X El Capitan will be available for developers as of today while public beta will come in July, with general release in the fall. Good side of the story is that the update will be free.