Aggressive GPU strategy may help drain MacBook Pro batteries

Stephen Withers
Wednesday, 05 May 2010 15:08

Opinion and Analysis

A graphics-related feature of the i5 and i7 based MacBook Pro models may be responsible for some users experiencing shorter than expected battery life.

One of the features of Apple's current i5/i7-based MacBook Pro models is automatic graphics switching. The idea is that the system uses either the integrated graphics controller or the Nvidia GPU as required by the software that's running.

Previously, users had to manually select the desired graphics controller in the Energy Saver preference pane, and a logout (or restart) was necessary before the new setting came into effect.

That was less than ideal, and automatic switching sounded like a welcome improvement.

The problem is the way Mac OS X determines which controller to use. According to Snapz developer Matt Slot, "If any active applications links to the high performance graphics libraries (OpenGL, OpenCL, CoreImage, etc), the system automatically switches to discrete graphics mode until that application quits."

This means running various relatively undemanding applications that use these APIs will activate the Nvidia GPU, leading to a significant drain on the battery.

Which applications cause this problem? See page 2.