Thunderbolt 27" Display Question

Discussion in 'Mac Accessories' started by gmmiller20, Dec 12, 2012.

  1. gmmiller20 macrumors newbie

    Oct 23, 2012
    I have a rMBP 15" that I have been using with a 24" Apple monitor. I just purchased a Thunderbolt 27" so I can hook up 2 monitors in clam shell mode. I have the Thunderbolt plugged into 1 of the Thunderbolt jacks and the 24" mini dvi plug going into the other Thunderbolt jack. I have everything working fine but I can't configure the resolution on the monitors correctly.

    The 24" is fine. It is set at Best for Display mode which happens to be: 1920 x 1200

    The 27" Display is way to small when it is set at Best for Display (2560 x 1440) but when I switch it to the next scale down which is 2048 x 1152 the monitor appears fuzzy. I would really like to use the suggested scale of 2560 x 1440 but need each application to display a little larger.

    Anyone have a solution?
  2. akm3 macrumors 68020

    Nov 15, 2007
    There is no 'solution' because there isn't really a problem everything is working as it should. Running monitors at non-native resolutions make them fuzzy. 27" has higher pixel density so things appear smaller. You'll have to move the monitor closer to you or sit closer if your eyesight can't tolerate the 27".
  3. gmmiller20 thread starter macrumors newbie

    Oct 23, 2012
    AKM, I am a little confused. I have an older 24" Apple Cinema Display and when I plug the rMBP into it, it increases the size of everything proportionately. But with the Thunderbolt 27" it seems when the rMBP is plugged in that the proportion stays the laptop sizing.

    Just trying to understand the situation better.
  4. Lennyvalentin macrumors 65816


    Apr 25, 2011
    The thunderbolt display screen has a higher number of pixels per unit of length (be it imperial inches for murricans, or metric cm for the rest of the world ;)), that's why things appear smaller on that screen.

    Since LCD screens are made up of discrete pixels (triads of sub-pixels, actually), you can't scale the resolution smoothly except in evenly divisible integers of the native resolution. If you choose something that isn't an even number the computer/display has to re-scale the smaller image to fit all of the screen pixels, which creates either fuzziness or blockyness (I get blocky myself on my '11 MBP + TB Display when running in a non-native resolution)...
  5. akm3 macrumors 68020

    Nov 15, 2007
    OK that's interesting, I'm possibly wrong I don't own a rMBP or a Thunderbolt display. I misunderstood you, sorry.
  6. Sean Dempsey macrumors 68000

    Sean Dempsey

    Aug 7, 2006
    The 27" resolution is just that, it's high. When you plug in your laptop, it renders the OS X desktop at 2560x1440. If that appears "smaller" it might be - your rMBP has an effective resolution of 1440 by 900 - that's quite low, so the UI appears larger. That's why you say it "increases proportionally." Don't worry about the retina pixels, that makes it more sharp, not bigger or smaller.

    The physical pixels-per-inch on the 24" is around 94. For the 27" it's around 110 pixel per inch. That's an 18% difference - meaning that a physical 1 inch box on the 24" will then be around 8/10ths of an inch. If you were to run the rMBP at it's real resolution, the ppi is 220 and a 1 inch box on the 24" would be less than half an inch on the rMBP.

    So your 24" literally has 1920x1200 physical pixels. So when you use that one, it looks fine. The 27" has 2560x1440, so when you use that resolution, that's fine too.

    If you try to scale the 27" down, you will get fuzz. Unless you cut the resolution in half - 1280x720 - it can't use the pixels in exact rations, so you get "split" pixels that create the fuzz.

    There's no way to make the applications bigger, that's just how they render on the 27". Sit closer to the screen.

    But rest assured - there's nothing wrong. The 27" is just large and in-charge.

    See in this graphic, the lines on the left are lined right up with the pixels. But on the right, they aren't exactly on each pixel right on the dot, so the computer does some anti-aliasing to make it look like it is.

    But rest assured - there's nothing wrong. The 27" is just large and in-charge. I'd just try and get used to the blurryness, or the native resolution.

    Attached Files:

Share This Page