Mac Mini 2012 second drive gets slow

Discussion in 'Mac Basics and Help' started by CTYankee, Oct 11, 2016.

  1. CTYankee macrumors 6502

    Jul 18, 2002
    I have a 2012 Mac Mini with a 500GB SSD in one drive slot and the stock 1TB HD in the second. Recently I found that the 1TB HD will get slow:

    -format drive it works fine for a while
    -drive benchmarks show it can read/write around 100mb/s
    -eventually I'll test again and the write speed is around 100mb/s, but read drops to 10-30mb/s
    -if left long enough it will get hung up on a big enough file that it just freezes the application.

    I use it for my EyeTV Archive. This means that when the drive gets slow ETV take a long time to open. It seems the video files recorded may also be less than perfect. Sometimes the audio is out of sync or the video freezes. I'm not sure if thats an issue from the drive or due to the antenna losing a good signal.

    I've reformatted the drive 3 times now. Each time it works and tests fine for a time. Usually just a week or so now before it gets slow. I've used Tech Tool Pro to scan for bad blocks. It does not find any, but it never finished either. After about 2 hours it gets so slow it would take 15+hours to finish. It seems the more the drive is used the slower it gets. Very odd. No sounds or other sings of bad blocks or a failing drive. Other drives (external WD duo, WD MyBook, and the system SSD) are all fine.
  2. Fishrrman, Oct 12, 2016
    Last edited: Oct 12, 2016

    Fishrrman macrumors Pentium


    Feb 20, 2009
    Could it be a "hard drive throttling issue" ....?

    NOTE: I DID NOT WRITE the following information. I archived it having seen it over at
    This may be of use:
    also see:

    Michael Schmitt
    (2016-10-02 at 21:10)
    brianvt Wrote:
    The other day I received a replacement backup hard drive to replace one that went bad: The problem emerged when it took 40 hours to run a Time Machine backup after upgrading from Mt. Lion to El Capitan a couple of weeks ago.

    There may have been nothing at all wrong with the hard drive.

    Starting with OS X 10.9 Mavericks, Apple make a kernel change that causes it to aggressively throttle low-priority I/O that hits spinning metal hard drives (SSDs are apparently given a pass). Rumor is that this was an attempt to fix performance problems, but it has a major side effect, because Time Machine backups are run as low priority I/O.

    The result is that Time Machine backups run at a snail's pace, even if no other applications are running.

    You can disable throttling of low priority I/O by entering a terminal command:

    sudo sysctl debug.lowpri_throttle_enabled=0

    This makes a world of difference. This weekend I attached a new drive to Time Machine on a SSD-less machine running El Capitan. It was going to take it a week to backup a couple hundred gigabytes. After disabling the throttling, the backup completed in an hour or so.

    Also, El Capitan tries (and fails, unfortunately) to fix the problems where Time Machine misses and drops backups of files. It appears that the first time Time Machine is run under El Capitan it does a very deep scan, to try and repair the missed backups from previous OS X's. So the deep scan combined with the I/O throttling makes the first backup run a very long time.
    (end of archived material)

    As many posters have reported since the release of Mavericks, it seems that Macs with internal platter-based hard drives often seem to "run slowly" vis-a-vis Macs with internal SSDs.

    I'm wondering if the "HDD throttling issue" could be a major factor behind this.

    Anyone reading this, who is running El Capitan or Sierra from an HDD ought to give this command a try...
  3. CTYankee thread starter macrumors 6502

    Jul 18, 2002
    Thanks, that may have done it. It is still early, but seems to work. I ran the speed test....slow. I restarted and tested the disk...slow. Made that change in Terminal, ran the test...back to normal speed.

    I'll update after a few days/weeks to confirm this does fix it long term.
  4. CTYankee thread starter macrumors 6502

    Jul 18, 2002
    Sighhhh. That lasted all of a day. Now the drive is completely unresponsive. So too is my USB backup drive (that one is only used by the finder/system and carbon copy cloner). Its weird, they get like this but Tech Tool and Disk Warrior can't seem to find anything wrong with them. I have other USB drives that are unaffected. Very odd, I've not seen this before.

    When I upgrade to Sierra it will be a clean install to hopefully flush out any software issues causing this.
  5. Cordorb macrumors regular

    May 8, 2010
    I would use an external USB-3 boot disk with a new system. your internal may be failing.

    You may want to double check temperature.

    I use a third party fan control as I have replaced my internal drives with SSD units.

    I use a OWC 4 bay thunderbolt external box filled with SSD's now but even when using the USB-3 ports that was faster than my old internal disks
  6. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    OP, I own several 2012 Mini Servers, which I opted for after a couple of experiences like you're having. You're not the only one. Some of the 2012 non-Server Minis had issues with the upper bay data supply, which we discovered a few years ago - so we opted for the Server version instead. I browser iFixit's forums on occasion, and bookmarked this post: - see that OP for a description similar to yours...

    The fixed SATA III and multi-speed drives in our non-Server Minis defaulted to SATA I speeds, and were as slow as you're describing here. We have no such issues with the Mini Servers, all 7 of them. You may have one of those affected Minis, and, if that's the case I'd spend my coin on USB 3 DAS units - but, that's my opinion here...
  7. CTYankee thread starter macrumors 6502

    Jul 18, 2002
    Thank you, campyguy. That does sound like it may be the issue. It is the non-server version with the second drive added. THought not sure why that post mentions optical drive, these never had an optical drive. It is odd how it just started recently. I had been using this configuration for 6 months or more. It just started in the last few weeks.

    It was a dual 1TB set up as a 2TB RAID. That broke down, one drive had back blocks. So I pulled the bad drive and replaced it with a SSD. The SSD is in the drive bay that is easy to get to (when you have the mini open and upside down the SSD is in the bay thats right there, easy to get to).

    If I reformat the drive it runs fine for a few days, then gets slow. Restart might reset the speed, but I need to test that out. It definitely didn't do this before so I'm not sure why it would start now. The terminal trick also gets it back up to speed, but then the setting reverts back somehow.

    If I put a SSD in there, would that work? I need to check the specs to see if those Autosense, but maybe that just applied to HD.

    External storage may be best. I am running low on space with my photos and videos and have been looking at an External USB 3. Nice portability too as I upgrade systems: Mac Mini, Mac Pro, Macbook Pro...anything will be OK, much more versatile than internal storage and certainly faster.

    Any suggestions on units?
    --- Post Merged, Oct 15, 2016 ---
    I've temporarily moved my EyeTV archive to an external USB 3 drive. If it works fine, then I can rule out OSX/EyeTV weirdness making the drive run slow. I'll then look to a DAS for all my media needs.
  8. mrkapqa macrumors member

    Jan 7, 2012
    Italy, Bolzano/Bozen
    Hello , i did not know that you can install 2 harddrives in a Macmini 2012. Can you do that yourself easily and are both spots Sata3? Please enlighten me on that. Thanks
  9. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    I only have conspiracy theories about "why" that issue occurs with some mid-2011 and 2012 Mac non-Server Minis (and some earlier Mac laptops). One of my reasons for calling this bit a conspiracy is from my years working around machine shops - the use of "what's laying around" for spare parts by mechanics (the machine shops I've worked in measure in acres, not square feet...) has led me to think that old parts that were just laying around found their way into the Minis. The bit that - in my mind - backs up my crazy feeling in the Mini was Apple's use of the fixed SATA II Toshiba SSD used in the BTO options and dual SSD model of the 2012 Server - seemingly a gimped drive when faster options were already available for about the same price. Hmmmm...

    I wouldn't be surprised to see some of the earlier-than-mid-2011 Mini hardware - which had optical drives - installed in later non-Server Minis. Also, IMHO, someone with Apple likely told the Mini hardware designer for the 2014 unit to stop using 5-year-old crap and redesign the innards of the new model...

    What I have read about Apple's hardware choices back then were at-times questionable, like the use of the problematic Nvidia MCP79 chipset in some of the 09 MBP which rendered SATA III SSDs pretty much useless at SATA I speeds; SATA III SSD upgrades in that MBP would work great, and then they wouldn't... I wouldn't be surprised if some of those Nvidia chipsets in later single-drive Minis, like the one you've got.

    IMHO, there's nothing you can do with a drive that isn't a fixed SATA II drive like one of the SSDs used in the 2012 Mini at the time. I've not taken the time to research such a drive as I moved on a few years ago, and that your Mini's chipset for the upper drive might be "failing" (I'm reaching with this bit, but IMHO Apple likely didn't think at the time people would take apart their Mini and stuff another drive in it or they'd just buy a Server like I did).

    I'd stick with DAS - all I buy now are the G-Tech G-Drive units ( - either the 4TB or 6TB drives are my "sweet spot" for DAS and capacity/price/warranty. They're faster than what you need, but they're perfect for me and my needs. I'm waiting to see if they update the case to the new USB-C interface, but that's just picking nits with these units as I just want to simply my cabling that lays around, and G-Tech has already started adding that interface to some of their newer products. Cheers!
    --- Post Merged, Oct 15, 2016 ---
    It's not "easy", but it's doable.

    But, read my previous posting - you may have issues with the Mini's actual interface, and I don't have the background to offer which chipset is in your Mini. I bought Mini Servers so I wouldn't have to futz with it after a couple of experiences identical to the OP's. DAS is my recommendation for the single-drive Mini.
  10. Cordorb macrumors regular

    May 8, 2010
    Adding one drive in a mac-mini 2012 was not hard ( SSD in my case) and I tested first first on my older 2011 and both worked. Actually closing the box back up was the hard part as I had to do it twice as I forgot the RF shielding to prevent any bluetooth problems.

    I still think that just using a external USB3 ( the 2011 mac-mini is USB2) is almost as fast and thunderbolt more so but at a higher cost but you don't use those USB ports.
  11. mrkapqa, Oct 17, 2016
    Last edited: Oct 17, 2016

    mrkapqa macrumors member

    Jan 7, 2012
    Italy, Bolzano/Bozen
    Thanks, it really seems quite difficult , and from what i read, you need to buy an adapter kit? you i would prefer an internal SSD option and HDD or FusionDrive for keeping the Thunderbolt for a second monitor. Or is there any other way to install a second monitor? Can you actually on a single HDMI connection plug-in 2 monitors?
  12. admwright macrumors regular

    Sep 11, 2008
    We have a Mini 2014 with the stock 1Tb. It has been running very slow for a while now. I put this down to the drive getting full (less than 10% free space). But since moving off some file (>25% free) there is very little difference. So we seem to be seeing the same problem as you with just a single drive. :-(
  13. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    Getting at the upper drive is more a matter of patience and precision, made a bit easier by having the correct tools handy (both iFixit and OWC sell a tool kit just for this, in addition to the kit to mount a second drive) - but this bit is exactly why I bought the Server configuration. The single-most addition to my Mini Server (7 with my company and 1 for my own use) was to swap out the spinners for a Samsung 850 Pro SSD (2 1TB for my work units put in a RAID 0 configuration as they're used mainly for rendering, a 512GB for my personal unit); I picked the 850 Pro since it blows away other SSDs when used as an OS drive, although any SSD will boost disk performance. My only caveat is that I'd actually rather spend money first on a RAM upgrade - all of mine are maxed to 16GB, and if my Mini Servers weren't in some sort of production mode I likely would have left the spinners in and used the money allocated for disks on a solid DAS unit or two like the aforementioned G-Tech G-Drive units.

    I almost didn't upgrade my own Mini Server but found the 850 Pro on sale at Fry's at a really deep 1-day discount, priced lower than the same-sized EVO. I do use Photoshop and a couple of CAD apps on my Mini from time to time, then let it render BUT, I have a fast DAS connected as the scratch disk and it's the combination of the two that make the work fly (I still don't know why everyone doesn't take advantage of scratch disks...).

    As to extra displays, yep, there's a solid company that's been serving Macs for *years* but they suck at marketing to Mac owners - Matrox. Start here: and look to the "DP" (for DisplayPort) editions. Never mind bad reviews on Amazon and elsewhere - so many people picked the wrong model (all they had to do was pick up the phone and call Matrox - great customer service...) and Matrox simply appended the new model to the old model ordering portal on Amazon/Newegg instead of setting up a new product (dumb, that...). Make sure you match your needs carefully to your displays and what your wants are. The boxes work very well...

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