You should know the drill by now: every year Apple announces new desktop operating system in June, and by the end of October, it'll be ready for us all to play with. The latest release takes its name from the iconic Yosemite vertical rockface, El Capitan.

While the changes don't seem that big on the surface, there's a lot going on under the hood that could make this incremental upgrade one of the most significant to date. Here's what Apple is adding to OS X in October.

Improved Performance

El Capitan is an incremental upgrade rather than a major release (that was Yosemite, with its new flat UI and bold colors). Most features added by Apple are improvements of past technologies, and that should mean a smoother, more pleasant user experience in general.

Apple is throwing some numbers around to back this up, like the fact that apps now apparently launch 1.4 times faster than in Yosemite, that switching apps and displaying messages in Mail are twice as fast as before, and that PDFs now open at four times the speed in Preview.

These may seem like meaningless numbers attached to mundane tasks, but if performance has picked up similarly elsewhere, it's possible you'll notice a performance increase this time round. That's rare because it's commonly accepted that each upgrade introduces features which generally slow your computer down.

Another area where performance is set to soar is with Apple's implementation of their console-level core graphics technology, Metal. The company is touting a 40-50 percent increase in system-level graphics rendering, which could seriously improve Yosemite's occasionally laggy performance. A 10x increase in draw call performance (the time it takes the hardware to draw an object called by the graphics API) should improve gaming performance too.

Better Window Management

When your desktop becomes cluttered, your workflow becomes inefficient. Apple has taken a leaf straight from Microsoft's book and finally added an "aero-snap" feature of its own which allows you to pin two windows side-by-side just like iOS 9's new Split View mode.

In fact, it's called Split View here too, and it allows you to grab an app, drag it to the top of the screen and then position it alongside another app without creating mess. The division in the center can be altered depending on the app you're using, so you can set up Safari with a small TextEdit window for notes or check off songs on a Reminders list while you add them to your iPhone in iTunes.

Mission Control itself has also been revamped, with a new view that places each window on a single layer, without any stacking or overlapping. In fact, you don't even need to head to Mission Control to organise your spaces any more — just grab the window, head to the top of the screen and wait for the desktop organiser interface to pop-up.

Last of all, while it's not a window management feature it's bound to be useful — shaking your mouse from side to side will now cause it to swell to giant proportions so you can easily find it, particularly handy if you use lots of monitors.

A Better Spotlight

Spotlight was overhauled during last year's major revamp of OS X, and this year it's getting smarter still with the addition of natural language. That means you can talk to Spotlight as you would Siri, by typing as you would speak. It should allow you to issue commands like: "Pages document I worked on yesterday about iOS 9," or "emails from Jackson last week."

Spotlight also adds some new sources of information, including the weather conditions and forecast, stock prices, sports news like scores, fixtures and league tables and web videos from sources like YouTube.

Improved Apps

Apple hasn't introduced any brand new apps to El Capitan's included software, but it has made some large changes to existing apps. Most of these changes are designed to complement the improved window management tools, with the introduction of Split View opening up a world of productivity options to users.

Mail in particular has seen some changes, starting with an improved full-screen mode (which is good because it's currently a bit useless). Also new are iOS-style prompts that check your incoming mail for phone numbers or calendar invites and offer to add them to your contacts or schedule. Another feature ported from iOS is the ability to swipe horizontally on a mail message to quickly mark an email read or unread (swipe right) or to delete an email quickly (swipe left).

Tying in with the iOS 9 revamp, Notes gets a big overhaul and can now handle to-do checklists and note attachments too. This allows you to pin photos, videos, documents, audio recordings, web addresses and even locations to a note. It's not quite Evernote, but it's a big step up and it syncs for free with all your other Apple devices over iCloud.

Apple's Safari web browser gets a few small tweaks including the ability to pin and mute individual tabs, two features that most other browsers have by now. It's also possible to use AirPlay with web video now, which means rather than mirroring your entire screen you can choose just to share the embedded video with your Apple TV instead.

In other, less interesting changes, Maps gets mass transit information allowing you to get more accurate walking, subway, train, bus and even ferry directions in cities like London, Berlin and New York (with more set to be added) along with an easier way of sharing the route you just planned on your Mac with your iPhone.

Photos is probably the least interesting app to receive an update, adding third party editing tools (like filters and effects) and a long-awaited "sort by date" feature but probably not fixing the fact that you can't easily edit your originals with an external editor any more.

New Fonts & Better Unicode Support

El Capitan comes with a few new fonts, and sees the system-wide font change to San Francisco, developed for use on the Apple Watch to be highly readable at a glance. If you're bilingual or learning Chinese or Japanese you'll also see improvements to El Capitan's handling of these character-based languages.

Chinese users will see the new Ping Fang font and find that whether they use simplified or traditional Chinese the OS will better remember word choice, includes an enhanced prediction engine and provides access to frequently updated vocabulary lists. Inputting characters via the trackpad has also been improved, allowing for multiple characters in a row.

Japanese input has also been dramatically improved, with enhanced vocabulary and language engine that automatically transforms Hiragana into written Japanese as it is typed; and four new fonts.

Try It Out For Yourself

If you'd like to try out the pre-release for yourself, OS X has a public beta program. Simply head to Apple's Beta Software Program and sign in with your Apple ID and you'll be notified how to participate in the beta. Remember that beta software is unfinished and buggy, so it might not be the best idea to install the beta on your main work machine.

What are you most looking forward to from the new version of OS X?