Does the iMac burn extra power with a thunderbolt display?

omvs

macrumors 6502
Original poster
May 15, 2011
481
11
I've noticed my iMac (27", late 2011) burns a fair amount more idle power with an external DVI (or HDMI/VGA) display hooked up. iStat Menus shows the GPU power jumping by 20+watts, which I find a bit annoying... I'm guessing some power-saving mode of the GPU is being disabled in this case -- its not much less than the power when I fire up a 3D game like diablo3.

Does anyone know if the idle power is similarly high with a Thunderbolt display instead of a displayport variant? I was wondering if it might use a slightly different transport mechanism and avoid the problem....
 

omvs

macrumors 6502
Original poster
May 15, 2011
481
11
You cannot drive two monitors on the same amount of power required to drive one monitor.
The GPU may have to do a TINY bit more work, plus another PHY needs to be turned on. But thats not 20watts worth.

The max-power in 3D seems to be very similar with either just the internal display or with an extra, further suggesting its a bug.
 
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