External SSD for iMac mid 2011 21.5inch?

Discussion in 'iMac' started by timreespt, Aug 13, 2019.

  1. timreespt macrumors newbie


    Aug 13, 2019
    Ebersberg Germany
    Hi, I have no idea what I'm doing so if you're kind enough to respond to this thread, easy on the jargon please.

    I've got a very slow mid 2011 iMac 21.5inch. It's crazy slow now, literally taking 30 mins to get going. Even typing is delayed. I'd like to upgrade it with an external (I don't fancy taking it to bits) SSD but I'm not sure about cables other things.

    Which external SSD will work for me, do I need a specific cable (I think my USB sockets will be the old type?) I've also seen people talking about thermal cables? Do you have any other suggestions that may help upgrade this old boy up?

    Thanks a lot for your time.

  2. Bertrude, Aug 13, 2019
    Last edited: Aug 13, 2019

    Bertrude macrumors member


    Aug 2, 2010
    In order to make the most out of the external SSD you'll need to have one connected via the Thunderbolt 1 port on the Mac (it's the fastest one you have). The USB ports on the Mac are USB 2 so won't offer you the transfer speeds you're going to need.

    Something like this should suffice or an equivalent item by brands like LaCie or Buffalo (just make sure it's one with an SSD not a 2.5" spinning platter type drive):


    If your Mac is really that slow it might be a sign of the internal drive packing up or some other hardware issue. If you haven't done so already, I'd backup anything important to you first and foremost, just in case.

    What version of the operating system is it running? (click the apple icon at the top left of your screen and select 'About this Mac'). Perhaps you could post the info from the Overview tab (don't mention your Serial Number though)

    You could try resetting the VRAM by restarting the Mac with the Alt, Command, P, and R keys pressed simultaneously. Let the Mac chime for a second time before releasing the keys. That sometimes fixes some issues.

    You could try running First Aid on the drive from Disk Utility (in the Utilities folder that's in the main Applications folder) and see if that helps or reveals any issues.

    You could also open up the Activity Monitor (also in the Utilities folder) and see if anything is hogging resources/memory/disk use.

    If it's still really slow after that then perhaps it might be worth wiping the drive and performing a clean install of MacOS.

    I must add, I'm no expert and I'm sure others can offer more insightful advice than this. Hopefully there's some other things I've neglected that might also be helpful to you.


    Forgot to mention booting in safe mode and resetting the SMC:


  3. timreespt thread starter macrumors newbie


    Aug 13, 2019
    Ebersberg Germany
    Wow, thanks for spending the time writing all of that out. Very kind. I'll try all those things you mention. I'll also try it via the thunderbolt.

    The version is 10.13.6 High Sierra. 2.5ghz, intel i5. Memory 4gb 1333 Mhz DDR3, Graphics AMD Radeon HD 6570M 512MB.

    Thanks again!
  4. tassyk macrumors newbie

    Oct 7, 2013
    Get a local computer store to install an ssd. It’ll be like having a new computer. Even if you get an external ssd, your system will be running off a slow one
  5. mikehalloran, Aug 14, 2019
    Last edited: Aug 14, 2019

    mikehalloran macrumors 68000

    Oct 14, 2018
    The Sillie Con Valley
    I see you’re in Germany but they have Mac techs and hobbyists there who can do the install. Apologies for using US pricing but these items are available everywhere.

    Thunderbolt dock costs $179 plus the cable — yep, it’s extra ($25–$49).

    Add the cost of the SSD. These are pretty inexpensive and are as good as any others. 5 year warranty.

    Get an estimate from a local tech to have one installed. Also replace the NV RAM battery—CR2032 is fine—it adds 30 seconds to the job and will prevent problems that will be misdiagnosed as GPU issues. Labor around here runs $75.

    The dock + cable will cost a lot more than the bracket+temp sensor+battery+labor. If you install yourself (very easy), there are a few tools you’ll need.
  6. g5604 macrumors newbie

    Mar 20, 2008
    Was just going to post a very similar question.

    I have a late 2012, 27in imac. Was wondering it it worth trying to get a pci nvme sdd + enclosure or is there no point as I am limited to thunderbolt 1 and usb 3.0 ports?
  7. jeddouglas macrumors regular

    Dec 13, 2012
    Inverness, UK
    I had the same problem (although not as bad) and ended up adding 8BG RAM and an internal SSD (whilst retaining the existing HDD). The RAM is very easy to add on this model as there are spare bays to add modules and just involves removing a couple of screws. The SSD was a bot trickier, but I managed it eventually after buying the toolkit and watching the instruction videos available. It worked out a lot cheaper than the external option. It is now like a new Mac.
  8. weckart macrumors 601

    Nov 7, 2004
    Look at second hand Thunderbolt drives. The LaCie Rugged ones are very common in the UK and cheaper than buying a brand new TB SSD. Should be the same in Germany.


    So, about €46 for the TB adaptor. Throw out the spinner and replace it with an MX500.


    €66 for 500GB, which should be enough unless you want to wait for Black Friday/Cyber Monday when the 1TB drives should be not much more.

    A quick and easy upgrade for about €110-€120. I would still recommend opening up your iMac and replacing the internal drive. You will just need a hard drive thermal sensor cable.


    These are usually €40-€50. The whole operation isn't that difficult once you have got the glass off.
  9. Fishrrman macrumors P6


    Feb 20, 2009
    Thunderbolt2 external is the only way to speed it up without opening the case.

    I don't know what your financial situation is... but... if the speed of the 2011 is "getting you down" these days... perhaps it's time to start shopping for a replacement.

    The 2019 (even the Apple-refurbished 2017) iMacs are beautiful and quick!
  10. markturnip macrumors newbie

    Oct 14, 2007
    Almost purchased a StoreJet 500 drive to use as a Thunderbolt bootable drive for a 2011 iMac. Since I don’t wish to update internal as Mojave isn’t supported & useful to have a bootable drive.
    However the reviews state it’s not as fast as specs make out. Is there a better TB drive at similar cost?
    Should I be looking for a NVME based TB interface?
  11. ZeitGeist macrumors regular

    Mar 22, 2005
    The best upgrade you can do for your iMac is to have the internal drive swapped with an internal 1TB (or better) SSD.

    Otherwise, if going via the external route, you’d need a Thunderbolt 2 to drive case or SSD adapter.

    You could go with a Thunderbolt 2 to USB3 adapter, like this one, and use an external USB3 drive. Better than nothing but not optimal.

    Or, get this combination of a USB-C drive case (and you can put any drive or SSD in there) and the Apple Thunderbolt 3 to Thunderbolt adapter.




    ... plug the Apple adapter into the back of the case, and use a short Thunderbolt 2 cable to link it to your Mac. That’s the fastest connection you can get.
  12. padams35 macrumors regular

    Nov 10, 2016
    Only 4GB RAM? Upgrading to 8 or 12GB will solve half the slowness even with no SSD.

    Another option is a Firewire 800 SSD. Sequential read/write speeds are no faster than an HDD, but performance would probably still improve due to the lower latency delays on SSDs. Naturally an internal or Thunderbolt SSD would be better.

    The TB2 <-> TB3 adapter will not work for USB3 devices: (its only a wiring adapter, it doesn't translate Thunderbolt protocol to/from USB protocol). Since Thunderbolt provides less bus power than TB3 I'd only recommend this route for Thunderbolt 3 devices which have their own power supplies.

Share This Page

11 August 13, 2019