How to disable 1 of my 2 monitors?

[COINcoin77]

Hi,

First, I need to say that, regarding my problem, I wasn't sure if I should post in this section or in the 'MacOSX' one, but like I'm facing this problem on my Mac Pro 4,1...

So, I have a 8-core Mac Pro 4,1 with an Apple HD4870 to which are connected 2 screens:
the main one is a Dell U2410 (1920x1200, via mDP to DP adapter) that I use under OSX for photography retouching with DxO.
The other one is a 27'' (1920x1080, DVI) I only use for gaming under bootcamp.

When under bootcamp, I only need to turn off the Dell and the desktop is resized for only 1 display.

My problem is that, under OsX, even when the 27'' is turned off, the desktop is extended to this display, I can't find a way to deactivate the 27''.
I can't even set the displays as 'mirrors', as they have different heigts in pixels (1200 vs 1080), and then I get a Dell resized to 1080

The only solution I have right now is to disconnect the DVI cable of the 27'' when using the computer under OsX, which is %&*)(@#$ (see what I mean)

Anybody ever had this problem, or has any clue about how to deactivate one of the 2 displays under OsX?

Thanks for your replies, and apologies if I posted in the wrong section

 

[mjsmke]

if you want to use only the 27" for gaming. set the displays to mirror then turn the Dell off (i know it will be the incorrect res but it will be off).

Or just delete Windows

 

[Dr.Pants]

There's probably some BASH-fu that you can do... but mirroring sounds like the simplest idea.

 

[Hellhammer]

http://www.madrau.com/

SwitchResX is the only app that lets you do it AFAIK. It's well worth the little fee. Otherwise you need to unplug the cable everytime

 

[COINcoin77]

Thanks Hellhammer, I'll try that.