iMac super slow HDD Read/Write speeds

Discussion in 'iMac' started by LucaJoakim, May 4, 2018.

  1. LucaJoakim, May 4, 2018
    Last edited: May 4, 2018

    LucaJoakim macrumors newbie


    May 4, 2018
    Using Blackmagic Disk Speed Test on my 27" 2013 iMac, the Read/Write speeds that came out didn't go over 20 Mb/s. This makes the iMac basically unusable, as even Safari takes ages to open.

    We've recently had many login issues, as after putting the password it wouldn't login. After contacting the support, we run the First Aid and it said "Macintosh HD is OK". We've then completely reset the iMac and reinstalled the latest macOS. This didn't fix anything, as it still takes forever to turn on and the Read/Write speeds are still not going over 20 Mb/s.

    At this point I'm pretty sure all the recent problems we've had with the iMac were caused by the HD. Do you think that replacing the 1TB HD with a 1TB SSD could fix the problem? Or what other options do I have?

    The iMac's Apple Care expired already and I've seen companies that would replace the HD with a 1TB SSD for 499€ (circa 600$).
  2. Phil in ocala Suspended

    Phil in ocala

    Jul 14, 2016
    Let us bought this with a conventional hard drive....then decided you would open the computer up and replace it with a HDD and now you are unhappy with the way the mac performs????
  3. LucaJoakim thread starter macrumors newbie


    May 4, 2018
    No, I bought the iMac back in 2013 from Apple and never changed anything. Always had the same stock Hard Disk.
    Lately (after 5 years) it started giving the huge problems I wrote about in the post.
  4. keysofanxiety macrumors G3


    Nov 23, 2011
    Sounds like the HDD's failing. Even if it wasn't and the R/W speeds were consistent, you'd still hugely benefit from an SSD upgrade.

    Please could you run SMART Utility and screenshot the results to see how your HDD's health is:

    If the drive is failing or if you're looking to upgrade to an SSD, you wouldn't need to pay a third party to tear it apart and upgrade. You can run the OS through an external USB 3 caddy with a standard SATA SSD and it'll be practically identical in real-world performance.

    Let me know how you get on.
  5. Fishrrman macrumors P6


    Feb 20, 2009
    "At this point I'm pretty sure all the recent problems we've had with the iMac were caused by the HD. Do you think that replacing the 1TB HD with a 1TB SSD could fix the problem? Or what other options do I have?"

    You're correct -- it IS the drive that's slowing things down.
    But -- you don't have to pry open the iMac to make it run much faster.

    The quickest, easiest, cheapest and safest way to GREATLY increase the speed is to buy a USB3 EXTERNAL SSD, plug that in, and set it up to become your "external booter".
    You'll get speeds that are roughly 85% of what you would see if the drive was installed internally, but with NONE of the risk of "opening the iMac and breaking something".

    You might consider a Samsung t3 or t5 drive, or one like this:

    You DON'T have to buy a 1tb SSD.
    500gb or even 250gb will do the job and do it right.
    You should see your read speeds jump to around 420mbps and writes in the 300-350mbps range.

    Put the OS, apps, and your accounts onto the SSD, but leave "large libraries" (such as movies, music and pics) on the HDD. They don't "need the speed" and they'll work fine on the internal HDD.

    You want to keep the SSD "lean and clean" so it will always run at its best.

    Use some velcro to attach the SSD to the back of the iMac's stand, where it's out-of-the-way and out-of-sight. You won't even notice it's there.

    Again, this is the fastest and easiest way to "get more speed".
    And did I mention it was the safest, as well...?
  6. LucaJoakim thread starter macrumors newbie


    May 4, 2018
    Took me around 20 minutes to run this test. Not gonna lie, the results aren't looking good.

    Photo link is:
    Sorry for the photo quality but taking a screenshot and sending it to myself via email would have taken hours.

    Is having an external SSD really my best option? This HDD is absolutely unusable and even opening a small program takes ages.
    Some users recommended me to bring the iMac to Apple to get it checked and fixed, even if my warranty has already expired. What do you recommend?
  7. keysofanxiety macrumors G3


    Nov 23, 2011
    Holy guacamole. Mate your hard-drive is buggered.

    Yeah external SSD is fine. You could go to Apple to get it fixed but you’ll be paying through the nose for another standard HDD, when you could pay the same amount or less for a 250GB+ SSD running externally.

    I’d personally recommend my 10 step plan for a happy Mac:

    1) buy an external HDD enclosure, something like this:

    2) buy an SSD:

    3) Plug in SSD vis USB.

    4) Hold CMD + R on startup to boot into recovery partition

    5) Format the SSD through Disk Utility

    6) Select reinstall macOS

    7) point it to the SSD you just formatted and wait for the OS to install

    8) laugh maniacally as your Mac runs faster than new, then say “welcome to the party, pal” to your iMac

    9) realise your last quote has inspired you to watch Die Hard, possibly the greatest action film ever made.

    10) Buy popcorn and drink beer while you watch Die Hard. Clink the beer gently on your iMac as you drink to her new-found health.

    Okay, whilst the last few points are recommended, they’re not mandatory. That’s your best bet I’d say. :)
  8. MasConejos macrumors regular


    Jun 25, 2007
    Houston, TX
    I has similar issues recently. My 2010 iMac HDD was failing, everything took forever to run. I watched a video on how to replace the HDD on youtube and it didn't look bad. I ordered a kit from OWC and a "flash assisted" FireCuda HDD from newegg. (The flash assisted was a conventional HDD with about 8GB of flash. It's basically a firmware implementation of the apple Fusion Drive, where the firmware will move commonly used files into flash for faster loading. I don't have a comment on if it really works as advertised, but the drive was 2TB and was under $100).

    Doing the upgrade wasn't bad. It probably took about 30 minutes. The hardest part was removing and reinstalling the screws that hold the LCD in place. Some of the screw holes are right next to the rare earth magnets that hold the glass in place. The overall process is: Remove glass, unscrew screen, tilt screen forward, opening a gap at the top, disconnect cable, tilt more forward, disconnect cable, repeat one more time, remove LCD. From there the HDD is easily accessible. Then you just repeat the process in reverse to put it all back together. (I restored from a time machine backup. With the exception of having to reinitialize one or two things, everything was exactly as I left it)

    My mac now runs silently and efficiently; it feels like a brand new computer. It is totally worth the effort if you are modestly comfortable doing this sort of thing.
  9. LucaJoakim thread starter macrumors newbie


    May 4, 2018
    Haha not gonna lie, I laughed. However, I already watched Die Hard so I'll have a look for other movies.
    Anyway why do you recommend to buy an external HDD enclosure and an internal SSD? Is it cheaper than buying directly an external SSD?
  10. keysofanxiety macrumors G3


    Nov 23, 2011
    Yeah an external SSD is essentially the same thing, but they’ll charge more for welding together the case. It’s far cheaper to just get the enclosure and put the drive in.

    And also you can never watch Die Hard too many times. I’m deadly serious about that point.
  11. kschendel macrumors 65816

    Dec 9, 2014
    Your 2013 iMac is not the simplest thing to get open, thanks to the adhesive-mounted glass. (Unlike the magnetic mounts on older iMacs.) That's the main reason for recommending an external in the first place, and yes, putting the bits together yourself will save a few pennies. I'd say the arguments against going external are a) you lose the port, which may or may not matter; b) I'm not sure how the 2013 drives its USB, but if it's a single driver chip, loads through multiple ports will slow all of them down, again may or may not matter; c) lack of TRIM through USB, d) general crummy aesthetics, and e) the HDD is still in there sucking power and making heat.

    Point (c) will likely generate heated arguments from both sides, and all I'll say here is that it can be quite workload and SSD dependent. Some workloads don't do what the SSD controller garbage collection might expect and writes can slow down badly. Some SSDs cope better than others. If you are an "average" user (email, web, bits of this that and the other) you can probably ignore TRIM. If it worries you, you can spend money, get a (€€) Thunderbolt enclosure instead, and solve all of the issues except (d) and (e).

    If it were my iMac, I'd install the SSD internally and make the HDD go away entirely, but I'll admit to having a bit of a OCD streak.

    (It IS possible for HDD's to fail in such a way that they hang the bus and then you have to remove it. That's not the usual failure mode though.)
  12. pam14160 macrumors newbie


    Jan 5, 2016
    This how I have mine setup and it works great...:)

Share This Page