Ars has a great technical article up about exactly how, when, and why Apple’s automatic graphics switching process occurs in its line of Macbook Pro laptops. For those not familiar with the automatic graphics switching technology, “the main goal…is to balance graphics performance with long battery life.” This battery saving, number-crunching goal is accomplished by toggling graphics processing tasks between two processors; a dedicated GPU, which consumes more power and provides high performance for applications that need it, and an integrated graphics processor, which consumes less power and does not provide high-end performance. Apple’s new graphics technology has been compared to NVIDIA’s graphics switching system — named Optimus. However, as Ars explains, they are different in two very important ways:
First… the switching is all handled automatically by Mac OS X without any user intervention (though there is actually a System Preference to deactivate it, if you choose). Apps that use advanced graphics frameworks such as OpenGL, Core Graphics, Quartz Composer or others will cause the OS to trigger the discrete GPU. So, when you are reading or writing Mail, or editing an Excel spreadsheet, Mac OS X will simply use the integrated Intel HD graphics. If you fire up Aperture or Photoshop, Mac OS X kicks on the NVIDIA GeForce GT 330M… The second way that it differs from Optimus is that the integrated graphics are powered down when the discrete GPU is active. This saves even more power than Optimus does, leading to a stated battery life as long as nine hours.
The graphics switching process, and the balancing act between horsepower and watt usage, is the future of high-performance mobile computing… that is, until better batteries start being produced. We’ve got the full article, in all its nerdy, technical glory, linked up for you.