Base 27” iMac (late 2012) - UI smoothness

Discussion in 'iMac' started by e271, Dec 20, 2012.

  1. e271 macrumors newbie

    Dec 20, 2012
    In AnandTech’s review of the 13” rMBP, it mentions that the UI frame rate is not always 60 frames per second but can drop significantly below this. Now the 13” rMBP’s resolution (2560 x 1600) is pretty close to the 27” iMac’s (2560 x 1440), and while the 13” rMBP has a weaker GPU than the iMac, the review mentions the frame rate appears to be limited by single thread CPU performance rather than GPU performance. (Quoting from the review: “In every situation where UI frame rate drops significantly on the rMBP, the offending application usually ends up consuming 100% of a single CPU core.”) The base 27” iMac CPU speed is 2.9 Ghz (turbo is 3.6) while the rMBP is 2.5 GHz (turbo 3.1) so the iMac’s single thread performance should only be ~20% greater.

    Here my question:

    does the base 27” iMac have a good (60 frames per seconds) UI frame rate?

    I’ve personally had a play around with one of these iMacs and don’t recall having any problems but my time was limited and I was probably not looking at complicated to display web pages etc.

    Those of you that have one of these, I’d love to hear your experiences to date.
  2. e271 thread starter macrumors newbie

    Dec 20, 2012

    Is this a complete non-issue??

    How about prior 27" iMacs? Have they ever had troubles in this regard?

    (By the way, I'm new to macs. Any comments would be greatly appreciated.)
  3. vnttr macrumors newbie

    Aug 18, 2012
    The slowdown is specific to Retina models because they don't operate at native resolutions. They typically render in 2x (per axis so 4x pixel count) one of the standard (pre-retina) resolutions and then scale to actual screen resolution.

    Hope this helps.

  4. WilliamG macrumors G3

    Mar 29, 2008
    My 2009 27" i7 iMac never had an issue with UI smoothness. I'd expect the 2012 to be likewise x 10000. :D
  5. e271 thread starter macrumors newbie

    Dec 20, 2012
    Excellent - thank you! That puts my mind at rest. Will probably put my order in later today :)
  6. crows macrumors member

    Nov 26, 2012
    I don't really get what you mean by the question the OS should be fluid, if you experience any slowdown with the UI it should be on a specific app, the OS draws the screen only where changes happen it doesn't draw every entire frame like games do...of course the OS can slowdown if 1 app is hoging all the resources but this kind of stuff is not due to any hardware configuration, I think its just the software you might be runinng and how it works..
  7. Onimusha370 macrumors 6502a

    Aug 25, 2010
    I got the base 27 inch, and its as smooth as butter mate :)
  8. e271 thread starter macrumors newbie

    Dec 20, 2012
    I have limited knowledge in this area - I thought the screen normally refreshes at 60 frames per second, if possible? Is this not the case?

    Anyway, the main thing I wanted to know was whether the experience of using the iMac was lag free in general everyday use (so ignoring things like games, fancy video rendering software etc). For example, in the thread below, a rMBP user mentions poor webpage scrolling (Facebook, The Verge). I wanted to ensure this sort of thing wasn't an issue for the base 27" iMac.



Share This Page