Dual Monitor on iMac (Intel)


macrumors G5
May 2, 2002
The closest thing would be to mirror, and turn the brightness of the internal display to zero. The LCD pixels may still be getting power, and the GPU may still be doing extra work (I know my old PBG3 was slower when mirrored--may no longer be true) but the backlight will be off.

I do that sometimes when watching movies on TV--it's distracting to have them also be on my PowerBook screen at the same time.


macrumors 601
Feb 10, 2004
Trouble with this option (turning down the built in displays brightness) is the VRAM gets split between displays, so you will only effectively be using 64mb (or 128mb depending on the model) of VRAM.