About shared memory Some Intel-based Apple computers feature both an integrated Graphics Processing Unit (GPU) and a discrete discrete GPU.  Others may feature only one GPU, which can be either an integrated or disrete GPU.  While a discrete GPU provides high performance graphics support using discrete video memory, it consumes greater amounts of power than an integrated GPU.  An integrated GPU provides effective graphics support using much less power and shares video memory with the main system. For Mac computers with two GPUs, you can use Mac OS X to decide which GPU to use for rendering graphics.  Select the integrated GPU for longer battery run-time when high performance graphics is not required, or if you’re using applications with demanding graphics, select the discrete GPU. Learn more about the integrated GPUs available with Intel-based Apple computers and the amount of system memory they share.

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About integrated video on Intel-based Macs

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