There is no standard app for that. Only geeks will have the 3rd party app installed.On macbooks there's a gfx control app that overrides OSX GPU selection. I don't think a global control should be part of the browser. A web developer can easily offer the user a choice (like SD vs. HD) and set the hint accordingly. If anything the global control over power usage belongs into the operating systems settings, right next to disabling wifi, bluetooth, airplane mode etc.
That said, I agree that global control over power usage belongs
in the OS. Given the way the OS X Energy Saver preferences are set
up "automatic switching" is the choice that indicates you want to
prolong battery life. This thread is happening because automatic
switching apparently isn't smart enough.
Why isn't something like the following algorithm sufficient when
the user has selected prolong battery life?
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