Chris Foresman:
However, a number of readers have alerted Ars that it seems the battery life isn’t living up to the promises, and many suspect that the automatic graphics switching is the culprit. So we set out to investigate the issue.
and:
While it’s no surprise that Aperture, iMovie, or Photoshop cause the system to switch on the NVIDIA GT 330M in the Core i5 and Core i7 MacBook Pros, some rather “pedestrian” apps can cause the discrete GPU to turn on as well: Tweetie, Transmit, PathFinder, Skype, and NetNewsWire, to name a few. These apps aren’t graphics intensive, but they are the kind of apps that most people leave running all the time.
Ars concluded that the use of Apple’s Core Animation is what is causing these relatively small applications to turn on the high-powered graphics cards. My guess is that they are right, the fix though does not seem to be that simple. I would like to see Apple make a seamless fix for this, however if they can’t here is an idea: take a Spaces approach.
Currently with Spaces (Apple’s multiple desktop preference) you can select which apps show up on which screen, or every screen. Why not build in a preference for the auto graphics switching that allows the user to essentially ignore an app when it wants to switch to the higher powered card? That’s what I would do short-term.