Is it possible to switch between graphics processors on the "Unibody" MacBook Pro without restarting? Can you use both of them simultaneously for better performance?

The currently shipping "Late 2011" MacBook Pro models -- as well as the previous "Early 2011" and "Mid-2010" MacBook Pro models -- automatically switch between graphics processors depending on need and no restarting is required.

For example, if one is typing a document or listening to music, then the system is designed to use the integrated graphics to conserve battery life and it should only kick the dedicated graphics card into gear when you plug in an external display or it is needed for graphics intensive tasks such as gaming or 3D animation (any application that uses OpenGL or Core Graphics among other technologies).

Switching Graphics Processors Manually

Automatic switching is convenient, there certainly are times when it would be desirable to be able to manually switch between graphics cards. For example, if one is gaming on a long plane ride, battery life could be more valuable than frame rates.

On the "Mid-2010," "Early 2011" and "Late 2011" MacBook Pro models, Mac OS X allows one to manually turn off the integrated graphics processor, but not manually switch to it to conserve the battery. Additionally, there are times when an open application will force the system to use the dedicated graphics processor even when it is not necessary, negatively impacting battery life and there is no easy way to tell which application is the culprit.

However, as first spotted by Engadget, Cody Krieger's gfxCardStatus menu bar application makes it possible to easily switch between graphics cards manually and displays which applications are using the dedicated graphics card, too.

Earlier "Late 2008" and "Mid-2009" MacBook Pro models equipped with dual graphics processors do not automatically switch between the two depending on need. As reported by Gizmodo, NVIDIA representatives reported that the hardware in these models is capable of switching graphics processors "on-the-fly" without restarting the computer or logging out.

However, for the "Late 2008" and "Mid-2009" systems, Apple requires one to select either "better battery life" to activate the integrated NVIDIA GeForce 9400M or "higher performance" for the dedicated NVIDIA GeForce 9600M GT in the "Energy Saver" control panel. In turn, it is necessary to "log out for the new settings to take effect."

Needless to say, this is less convenient than being able to switch between graphics processors "on-the-fly" and many were hopeful that this functionality would be added in future versions of Mac OS X. Although Mac OS X has yet to add this support, the gfxCardStatus menu bar application offers support for switching between dedicated and integrated graphics on the 2009 models as well. If you find this application useful and would like to support its continued development, a donation is strongly encouraged.

Both Graphics Processors Simultaneously

The NVIDIA website also confirms that the chipset for the graphics processor used by the "Late 2008" and "Mid-2009" is capable of using both graphics processors simultaneously using "GeForce Boost" technology, which:

Spreads the graphics-processing over both GeForce GPUs (discrete GPU and motherboard GPU) in a Hybrid SLI notebook, increasing gaming performance up to 80%.

Unfortunately, "GeForce Boost" technology is not supported on the "Late 2008" and "Mid-2009" models nor is it supported on the "Mid-2010," "Early 2011" or "Late 2011" models either.

No doubt, using both graphics processors at the same time would be murder on the battery life. However, those interested in getting maximum power for gaming or graphics applications no doubt would be thrilled to have the option.

Graphics Switching Summary

Ultimately, only time will tell if Apple will decide to add more graphics card control on the "Late 2011," "Early 2011" and "Mid-2010" MacBook Pro models or add support for automatic switching between graphics processors -- or at least the ability to manually switch between graphics processors without requiring one to logout -- for the older "Mid-2009" and "Late 2008" MacBook Pro lines.

Likewise, no one knows if Apple will add support to use both graphics processors simultaneously in future updates to the operating system, but one would be wise to not hold one's breath waiting for such additions. Nevertheless, it is entirely possible that third-party software like gfxCardStatus may offer all the functionality you need.

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