Slow 2015 21.5" iMac

Discussion in 'iMac' started by camner, May 22, 2017.

  1. camner macrumors regular

    Jun 19, 2009
    I'm trying to troubleshoot my daughter's 2015 21.5" iMac (8GB/3.1 GHz/1TB HDD, not Fusion Drive), which seems to be very slow. It's running 10.12.4

    First, it takes about a minute to startup to the login screen, and then takes another 3 minutes to stabilize at the Finder.

    1. Is a full minute from power on to login screen reasonable?

    2. Seems as if 3 more minutes to system stabilize is excessive. Login items include Dropbox, iTunesHelper, Spotify, Show Desktop, and AdobeResourceSynchronizer

    There are many times when the beachball spins for a long time. It seems that whenever the computer is running a significant app (even if total CPU load is about 15%) everything else, from using Quick Look on a PDF, opening System Prefs or any other app, etc., takes a long time (up to a minute for to open System Prefs). Even the keyboard hiccups...while typing this post, the cursor often stalls, particularly if I backspace to correct an error).

    The iMac was set up initially by migrating (at initial setup) from a MacBook Pro.

    Short of doing a complete system rebuild (fresh install), are there some troubleshooting steps I can consider?

  2. nambuccaheadsau macrumors 68000


    Oct 19, 2007
    Nambucca Heads Australia
    About a minute is average for a 5400rpm drive. Get all those login items out of there.

    I can see why it is having problems. Migration Assistant is designed to move apps etc over after a clean install of OS X has been carried out, not to copy the entire OS from one Mac to another, let alone a different model. No doubt youn will get varying advice, but if it were mine I would backup and use Internet Recovery to format bthe drive and download a nice clean version of Sierra and updatento OS X.12.5.
  3. camner thread starter macrumors regular

    Jun 19, 2009
    Thanks for the reply. I didn't use Migration Assistant to move the operating system over; I just used it to move over apps, user preferences, etc.
  4. sboychuck macrumors regular

    Sep 19, 2014
    Thousand Oaks, CA
    Have you tried using First Aid under Disc Utility? Have you scanned it for a virus and malware?

    My mom has a 2011 21-inch iMac that I am going to pull out the spinning hard drive and install an Crucial MX300 525GB SSD into it. I may not be able to get the full speed out of it, but it will be a lot better that what is in it right now. Her's is getting slow as well.

    If you have a good back up of the files, and a time machine backup, maybe it is time to re-format the drive and install Sierra again? May not be a bad idea to use CCC and clone the hard drive in case the backups fail as well.

    Just a few thoughts.
  5. nambuccaheadsau macrumors 68000


    Oct 19, 2007
    Nambucca Heads Australia
    Virus? What is a virus on a Mac OS X? A world first?
  6. antonypg macrumors member

    May 8, 2008
    A friend of mine bought her young son a MacBook Air, within two weeks it was grinding to a halt. I ran Malwarebytes Anti Malware package and it found 12 items of Malware. Once these were removed it was back to full speed again.

    There is a lot of Malware out there, but most Mac users are quite careful and don't come across it. Kids who tend to go to "free download" sites will come across a lot of Malware installers.
  7. Fishrrman macrumors P6


    Feb 20, 2009
    "First, it takes about a minute to startup to the login screen, and then takes another 3 minutes to stabilize at the Finder."

    The problem is that you're trying to run Sierra using a platter-based hard drive.
    No matter what you do, it's probably going to be "on the slow side".

    I realize that "perception of the computer's speed" is a personal thing, and what may seem slow to me, won't be slow to you. Nevertheless...

    ...If you REALLY want to speed the iMac up, do this:
    - Get an EXTERNAL USB3 SSD. It can be either a pre-packaged "ready-to-plugin" unit, or you could buy a "bare" 2.5" SSD and then put it into a USB3 external enclosure that supports UASP.
    - Initialize it to HFS+ with journaling enabled.
    - Install a copy of the Mac OS onto it. It could be Sierra, but I prefer El Cap right now.
    - You might even be able to use CarbonCopyCloner to selectively "clone over" the OS from the internal drive. By "selectively", I mean that you would have to "leave some stuff behind", like large libraries of pics, movies, music in your daughter's home folder. (They can be EASILY accessed from the external boot SSD)
    Note: CCC is FREE to download, and it's FREE to use for the first 30 days. One of the best pieces of Mac software out there.
    - Set the startup disk pref pane so that the external SSD is now the boot drive. You can velcro it to the back of the iMac's stand, up and out-of-the-way.

    Put the OS onto an external SSD, and you will be AMAZED at the improvement in performance. Read speeds (such as at bootup) will increase at least 4x.
    It's really that simple.

    NOTHING ELSE you try is going to make that much of an improvement.
    That's the downside these days, of buying a Mac that has only a platter-based hard drive inside...
  8. cynics macrumors G4

    Jan 8, 2012
    I'm not sure if this was established but was there ever a time where this iMac felt fast? If not what is your point of reference (the MBP)?

    If you leave the machine on and wait for everything to "stabilize" does it feel "ok"?

    Like others I'm thinking you are just experiencing how a HDD (and a relatively slow one at that) feels, again depending on your point of reference. My iMac also has a HDD (7200rpm though) and it was fine until I started building machines with SSD's. My quick and dirty solution (which you can't do unfortunately) was to max out the RAM and never turn it off (its serves my iTunes collection anyway). So in day to day task its relatively quick. When a iMac is asleep its using virtually no power, my UPS bounces between 0-1 watt when its asleep so don't worry about electric bills.

    For the life of me I can't understand why Apple would even consider 5400RPM HDDs. Fusion 24gb SSD + XXXgb HDD should be the bare minimum for them. Someone could argue cost and profit margins but like the OP this doesn't leave a good taste in their mouth and just gives the impression Macs are slow and then they won't buy another one which nullifies any sort of cost savings Apple may have benefited from.

    I would manually save all your files to an external source. Install a fresh copy of MacOS and manually move the files back once you establish if its fixed. If its not and your confident the issue is with the HDD you'll options are limited, sell/return it and buy one with an SSD, open and modify it with an SSD, or an external start up disk (recommend Samsung T3).
  9. camner thread starter macrumors regular

    Jun 19, 2009

    Thanks both for your 'extensive reply. Now that I've worked more with my daughter's machine, I do think that a lot of it is due to the 5400rpm HDD. I am a bit surprised by how long it takes on boot up for the iMac to stabilize, since she just doesn't have that many startup items.

    The other thing that surprises me is the number of times there are spinning beach balls on relatively routine operations, particularly when another app is processing something.

    My daughter didn't consult with me this time before buying the iMac. I would have suggested at least a fusion drive (which is what I did with a 27" iMac earlier this year!)
  10. cynics macrumors G4

    Jan 8, 2012
    What is your definition of a virus? Many use it as an all encompassing statement for malware. Plenty of malware has targeted Macs over the years.

    Years ago I was "infected" by the DownLite trojan. It was packaged with the DivX player I downloaded in attempt to find a h265 video player.

    Thankfully the symptoms were more of a nuisance then nefarious and someone on this forum recommended the program "Malwarebytes" which was quickly able to identify it and remove it. In the process it clued me in on its source (the DivX player) which I promptly purged from the system as well.

    I highly recommend everyone with a Mac download the free program "Malwarebytes". Its a very lightweight program, that doesn't run in the background or use any resources (you need to manually start it) and occasionally run it especially if something odd is happening. Since I got it, that one "infection" was the only thing it ever found.

    MacOS isn't impenetrable and even though my case was user error the risk are still very real. There is always that random program you need in a pinch so you by pass Apples dummy user protection to install something.
    --- Post Merged, May 23, 2017 ---
    Beachball can indicate other problems then just slow storage media which why I recommend a fresh install of the OS. The main time I see it is when I'm running out of memory, swap being used etc. This is usually related to a program that has decided to run amok (memory leak), two major offenders for me are Safari and iTunes....iTunes will just sometimes ramp up CPU usage doing what appears to be nothing although I usually notice higher CPU temps before beachballs. Say for example swap is being heavily used, an SSD can fix this however in reality its only masking the problem. And this is just because the SSD is fast enough for you to not notice the swap usage.

    Scroll through activity monitor when you see a lot of beachball activity and see if anything is suspicious with memory usage and the processes using CPU (even if they aren't maxing out CPU usage). If its something obvious (like Safari for example) try to use a different browser for a little bit and see if it gets better.

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9 May 22, 2017