Using monitors at non-native resolution

Discussion in 'Mac Accessories' started by say19, Nov 19, 2014.

  1. say19 macrumors member

    Oct 19, 2014
    Hello. I've read various contradictory things about this so I thought maybe someone here could shed some authoritative light.

    What I want to know is whether there is any performance penalty for running a monitor at lower than its native resolution.

    The scenario I am envisaging is as follows. Say you run a game on two monitors. Monitor A is a 2560x1440. You run the game at native resolution. Monitor B is a 4k. You drop the resolution and run the game at a non-native 2560x1440.

    Will performance be identical in these two cases, all other things being equal? I.e. do you sacrifice anything by forcing a 4k monitor to "think down"?

    Supplementary distantly related question. Many monitors when listing response time offer some kind of "fast mode" with a slightly lower response time. What is the penalty for running a monitor in "fast mode" i.e. why wouldn't one have it on all the time?

    Thanks for any enlightenment!
  2. VirtualRain, Nov 20, 2014
    Last edited: Nov 20, 2014

    VirtualRain macrumors 603


    Aug 1, 2008
    Vancouver, BC
    You may have been hoping I stay out of your thread... if that's the case I apologize. ;)

    Of course, gaming at a lower resolution will increase performance, regardless of what the monitors resolution is, because the less pixels your GPU has to render, the more frames per second, it can achieve...which I'm sure is your intent behind gaming at a lower res than 4K. :)

    In your scenario, where all you change is the monitor, FPS will not change as that's strictly a function of the computer. However, monitor lag might increase slightly if you ask the high-res display to scale your low res input to its native res (how much and whether it's even noticable is anyone's guess). However, if you don't care to have black borders around your content, then there should be no penalty (assuming these choices are available in settings).

    I don't know how those fast response modes work, so I can't answer that. I have heard that Dell displays with multiple inputs are notoriously laggy from hardcore gamers so if you're considering one of the new Dell's it might be worth waiting for a review.
  3. Mikael H macrumors 6502a

    Sep 3, 2014
    Some additional comments to @VirtualRain's reply:
    I've seen claims that seem to indicate that the more inputs a monitor has, the higher the chance that its onboard controller may introduce some lag. This surely depends on a number of factors, so I wouldn't be so bold as to claim this as a general fact, but if you think of it as an extra signal converter that needs to do some specific work, it makes sense that not all hardware and firmware holds the same high quality and specs.

    Specifically when it comes to scaling-induced lag, a gamer forum I visited made tests with a number of monitors of different sizes and native resolutions to check this claim, and according to their tests, the numbers were entirely within the margins of error of the test. So at least with screens built later than 2010, you're probably unlikely to suffer reduced speeds from the scaling.

    From what I've understood of "fast" or "game" mode, it seems to soften the image. This may indicate that it avoids using the brightest brights and the darkest darks when displaying a picture, so that pixels are less likely to need to change across a significant part of the gamut between white and black between screen refreshes. If so, you're trading color quality and picture detail for refresh speed when using this mode.
  4. say19 thread starter macrumors member

    Oct 19, 2014
    Both very useful and informative replies, thankyou! I feel pretty happy now investing in a 4k monitor. I have bounced back and forth but gaming is only one of my uses, and provided the panel turns out to be decent quality, I think 4k will give me longer use.

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