Released June 2012, Model A1278. Intel processor with Turbo Boost, Up to 512 MB DDR5 Video RAM

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Resolution output on mb changed when tb to hdmi plugged in


I plugged in HDMI on MB Pro mid 2012, via TB adaptor.

Immediately laptop screen went to 1920x1080... why won't it let me change resolution to higher when thunderbolt not plugged in?

I don't understand - if it can do higher resolution, why is it not allowed in desktop settings?

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Attached the OS Sierra desktop on laptop is at 1920x1080...


Answer this question I have this problem too

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and by downloading Setres X I managed 2560x1600... so clearly the display can do it.

Yet it's not 'default' in settings...


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Here's the specs for your system: MacBook Pro 13" 2.9 GHz i7 (Mid-2012)

Here's what the system is able to support from EveryMac: 1280x800

Apple reports that this system also supports:

  • 1152 by 720
  • 1024 by 640
  • 800 by 500 pixels at 16:10 aspect ratio;
  • 1024 by 768, 800 by 600, and 640 by 480 pixels at 4:3 aspect ratio
  • 1024 by 768, 800 by 600, and 640 by 480 pixels at 4:3 aspect ratio stretched
  • 720 by 480 pixels at 3:2 aspect ratio
  • 720 by 480 pixels at 3:2 aspect ratio stretched

Now here's the other shoe falling...

Intel HD Graphics 4000 services can't push two screens at different scaling or ratio's

Now the newer retina class systems offer deeper options MacBook Pro 13" 3.1 GHz i7 (Early 2015) for reference:

3840x2160 on two external displays via Thunderbolt 2, Alternately, it can support a single display up to 3840x2160 via Thunderbolt 2 and a single 1080p display at up to 60 Hz, 3840x2160 at 30 Hz, or 4096x2160 at 24 Hz via HDMI.

This series uses the newer Intel Iris 6100 graphics services.

Even still the internal display is not running in true higher screen resolution depending on your OS version. Here's a bit more on that: 4 Ways to Run a Retina MacBook Pro at 2880×1800 Native Resolution.

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Noticed it cannot do a different resolution on its builtin and output.. a bit lol..

so my mac is able to do 2560 x 1600 on its tiny 13''


It is i5 - 2012, not i7... but still, it is working fine in 2x its max 'displayed' reso. Why are they hiding these resolutions? This is more or less retina resolution...


No, your system can't push 2560x1600 as you have a non retina model. You would need an Intel Iris 6100 GPU to push that (a retina series system).

As far as the i5 Vs i7 the graphics services, both models use the same GPU design.

Your LCD can't support these other options. What you are seeing here is what the driver can support not what the hardware is able to support.

Think of it this way the speedometer in your car shows 160 MPH but can your car really go that fast? Nope!


it is more like... speed limit is 70, but your car can do 140!

Have you ever tried it? Because I've been with my hands inside pcs for a long time, when it doesn't work, there is NO picture on screen! Simple!

Now this one displays 2560x1600 which is 2 x 1280 x 800.

Retina does a scaling of 2560x1600 to 1280 x 800 ( 2 pixels per pixel)...

I am telling you, this is actually working. I don't think the crystals in the LCD will leak out crying their eyes out!



The pitch of the LCD panel pixels are not magically changing ;-}

What you are seeing is the internal display scaled to 1280 x 800, it's not 2560x1600.

If you are really pushing an external at 2560x1600 (the internal to 1280 x 800) in this series, it sounds like Apple fixed the driver which was a major shortcoming. To bad its still a hidden feature.

When we first looked at the 13" models we didn't like the fact the system was crippled. We went with what 15" models instead as our standard. Some executives bought their own systems which we still fix but they don't use the system with an external.


all I can say is I got 2560x1600 on both mac's 13'' and external display..


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