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 MacBook Pro "Core 2 Duo" 2.26 13" (SD/FW), "Core 2 Duo" 2.53 13" (SD/FW), and "Core 2 Duo" 2.53 15" (SD) only have a single "integrated" NVIDIA GeForce 9400M graphics processor with 256 MB of DDR3 SDRAM shared with main memory.

All other "Unibody" MacBook Pro models, however, have dual graphics processors -- a NVIDIA GeForce 9600M GT with dedicated GDDR3 SDRAM and the NVIDIA GeForce 9400M with 256 MB of DDR3 SDRAM shared with main memory.

The primary advantage of dual graphics processors is that it allows one to decide to either use a high powered graphics processor -- at the expense of battery life -- or a lower powered graphics processor -- at the expensive of performance.

As reported by Gizmodo, NVIDIA representatives have reported that the hardware is capable of switching graphics processors "on-the-fly" without restarting the computer or logging out.

However, MacOS X does not support this capability, and consequently, Apple requires one to select either "better battery life" to activate the NVIDIA GeForce 9400M or "higher performance" for the 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 dynamically switch between graphics processors without having to shut everything down and logout and many are hopeful that this functionality will be added in future bug fixes or versions of MacOS X.

The NVIDIA website also confirms that the chipset for the graphics processor 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, like dynamic switching, "GeForce Boost" technology is not supported by MacOS X either.

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

Ultimately, only time will tell whether or not Apple will decide to support "on-the-fly" switching between graphics processors or the ability to use both graphics processors simultaneously in future updates to the operating system.

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