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I have a retina MacBook Pro and 2 cinema displays attached to it. If I unplug the displays I get quite good performance in games, obviously when they are attached that's not the case (because the VRAM seems to be sliced to a third).

I've tried SwitchResX to turn off the built in display and the 2nd cinema display, but it doesn't seem to have much effect.

Unplugging them is not really an option (don't want to rip everything out every time I jump into a game for a couple of minutes).

Isn't there some other way to optimize performance (besides clamshell mode, though I would have to unplug the 2nd display either way)?

PS: The MBP is quite beefy (16GB ram, 1GB 650M, SSD), running Mac OS 10.8

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1 Answer 1

Preparation

  1. Turn off display mirroring
  2. This might be needed (or not): Put the menu bar on the external display. When this is not connected the internal will pick it up automatically. I didn't need to do this on OS X Lion 10.7.4 on my Macbook Pro but I've seen it mentioned.
  3. Open System Preferences and click “Mission Control”, then click on “Hot Corners”
  4. Select a hot corner and pull down the menu to select “Put Display to Sleep”. Then "OK".

Method

  1. Put macbook into normal clamshell mode (external display on, macbook lid closed)
  2. Using a hot corner (on the external display), put the external display to sleep like described in Preparation above (at the end of this step, you should have a closed macbook and external display off).
  3. Now open the macbook lid and the external display should switch back on automatically (while keeping the macbook display off), if not just tap a key on your bluetooth or wired keyboard. I haven't tried this with the internal keyboard.

You can verify this is so by having the display status on the menu bar and see if the internal display is listed. If not, it should be unused.

This method works reliably on my older Macbook Pro running Lion 10.7.4. Please try it very carefully and report if it worked out for you.

Credit to Paul Horowitz and user John, whose ideas I combined. See original here: http://osxdaily.com/2012/06/15/yet-another-way-to-turn-off-internal-lcd-display-of-macbook-pro-with-lid-open/

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I upgraded to OS X 10.7.5 and now this tip does not work, even though it did before in 10.7.4. Bug or feature? It would be interesting to know if 10.8 is any different in this regard. –  MiB Feb 7 '13 at 8:44

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