Will a clean install and restore make any performance difference?

Discussion in 'macOS' started by imahawki, Feb 11, 2015.

  1. imahawki macrumors 6502a

    Apr 26, 2011
    I have a 2011 i7 3.4 iMac with 16GB of RAM. In the last year or so it seems to be getting slower. I don't want to re-install all my apps so I haven't bothered to do a clean OS install. I've migrated every OS from Snow Leopard to Yosemite. If I format and install Yosemite fresh, but restore everything backup after, will that negate any benefit of a fresh install?
  2. Fishrrman macrumors P6


    Feb 20, 2009
    A very important question:
    What kind of drive do you have inside the 2011 iMac?

    Is it a platter-based hard drive?

    Macs with HDD's that were doing fine with Snow Leopard, Lion, or Mountain Lion -- can suddenly "get sluggish" when upgraded to Mavericks or Yosemite.

    The reason seems to be with all the processes that go on in the background, and the fact that with Mavericks, Apple changed the way that memory is loaded and handled.

    Whatever they did seems to put a lot of "performance pressure" on platter-based HDD's, while Macs with SSD's as their boot platforms seem to do fine.

    As you've discovered, RAM by itself doesn't seem to matter -- it's the DRIVE that makes the difference.
  3. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    If you erase then reinstall and restore afterwards, yes that completely defeats the purpose of a clean install since it just everything right back like it was.

    That machine should run Yosemite just fine. Look in Activity Monitor in the CPU section and sort by CPU% to see if anything there is chewing up CPU cycles.

    You might also trying running the app Etrecheck. It will highlight in red any add ons etc you have that are not compatible. You can post the results up here so we can have a look if you like.
  4. Bomb Bloke macrumors regular

    Bomb Bloke

    Feb 12, 2015
    Tasmania (AU)
    Mind you, if you don't restore the entire backup - just grabbing your personal Home folder - that'll indeed strip out nearly all of the clutter. The Migration Assistant allows you to pick and choose.

    Before setting out to update, it may be worthwhile creating a new user account, logging into it, and testing system performance there. This'll give you a loose idea as to how many of your "speed" issues are related to your actual account.

    Odds are, knowingly or unknowingly, you've collected a number of Safari addons over the years which're no longer compatible since subsequent OS updates have been installed. At the very least, you should consider cleaning these out before updating further.

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3 February 11, 2015