Boot from thunderbolt VS USB 3.0 external SSD

Discussion in 'Mac Accessories' started by MasterStewie, Dec 23, 2015.

  1. MasterStewie macrumors newbie

    Dec 7, 2015
    Hey guys,

    I've ordered my very first iMac and I'm a huge fan of SSD's. But because configurations where fixed I had to order one with the 1TB fusion drive.
    Because this is a big limitation of speed I searched around to have a solution for this and it appears that there are 2 choiches with similar speeds.

    Install OSX on an external drive with:
    1) USB 3.0 with UASP enclosure (I already have one)
    2) Thunderbolt enclosure which will cost around 100€ more

    I was watching an youtube reviews and there it appears that boot times from an USB 3.0 SSD aren't that good because the iMac has to start the USB controller or something. It took like 20s before it started to boot, once booted it worked great.
    An other disadvantage is the absence of trim but a samsung 850 pro 512GB has a very good own carbage collection which keeps the speeds high (from other reviews).

    Now for thunderbolt, I know this behaviors differently but I don't understand everthing about it. Is it correct that Thunderbolt is a more direct connection? Will it have the same waiting delay before booting up?
    I know for sure that Trim can be enabled so choosing a thunderbolt enclosure with a samsung 850 evo 512GB will have the same price as USB 3.0 with a samsung 850 pro 512GB with roughly the same performance.
    As last I've read that thunderbolt doesn't consume CPU processing power, which reinforces my thought about a direct connection.

    Is this correct or will there be no improvement on boot times for thunderbolt compared to USB 3.0 with UASP.
  2. Fishrrman macrumors Pentium


    Feb 20, 2009
    I don't think you're going to experience much "perceivable" difference in the boot times of a thunderbolt SSD vis-a-vis a USB3 SSD (so long as the USB3 enclosure supports UASP).

    They will be very close.

    You will not be able to use TRIM with USB3.
    HOWEVER -- in my experience going on three years now, the lack of TRIM makes no discernible difference insofar as performance is concerned over the long term. Others may disagree, but that's my experience and I'm a HEAVY user of the computer/drives involved.

    Something like this might do you very well:

    The 240gb version looks to be "the sweet spot", price-wise.
    You don't really need a vast amount of space on an SSD booter.
    It should hold your:
    - OS
    - apps
    - accounts

    ... and if you have large libraries of photos, music and movies, keep them on the internal HDD.

    I'm using a Sandisk Plus 240gb to boot and run my late-2012 Mini, and it yields read speeds around 426mbps and writes around 325mps.

    One last thought:
    Before you buy the external drive, run Blackmagic on the default fusion setup, and let us know what your numbers are.
    It might do pretty well, "as is"....
  3. MasterStewie thread starter macrumors newbie

    Dec 7, 2015
    The SSD on the fusiondrive is only 24Gb, probally fast but very limited in space. I will give the figures once I recieve the iMac.

    The reason why I want to take the 512Gb SSD is because without trim the performance is nearly as good as whit trim, from the 256 the difference is bigger. That's what I've read from reviews.
    On the other hand is a 256Gb SSD with TB around the same price as USB with 512GB.

    I will first run it like it is, I have no clue how big OSX is but I'm affraid the SSD part is to smal.

    I won't edit video or photo's, it is more a consumer device. Internet, mail, Netflix, OTT video app, VPN to work and some VM's will be the hardest task to perform. The Imac should do this with ease.

    If I understand coorect you can't get the same boottimes with external SSD as with internal? As the iMac is leased the first 3 years I won't open it up and stay external (or standard).
  4. ColdCase macrumors 68030

    Feb 10, 2008
    I was much happier when I switched from USB to TB boot drive, the Mac seemed so much more responsive, just snappier, and there was no worries about USB enclosure quirks. The net is full of those that are quirky with Mac OS, and every time a Mac OS gets updated, there is a good chance another quirk is going to show up. You need to carefully select the USB enclosure. USB is a wild west compared to the stable TB interface. Cost is a subjective thing. But if you ever want to RAID a couple drives for performance, TB is the only way to go.

    You will notice the difference in performance much more should you do some processor/disc intensive tasks like transcoding or video editing.
  5. Ray2 macrumors 6502a

    Jul 8, 2014
    If your described use is normal, there's no need to do anything.
  6. RevToTheRedline macrumors 6502a


    Sep 27, 2007
    The Akitio Neutrino Thunderbolt is a great option if you want full SATA support for SSD's externally, I can run SMART and TRIM to the 1TB Samsung 850 EVO SSD I put inside it. Came with a 120GB Sandisk U110 SSD but I sold that to a friend and made up some of the cost of the thunderbolt enclosure. I was unable to find any USB 3.0 option that could properly support TRIM, there likely isn't one but I could be wrong. But it was an important feature to me. So I didn't mind spending the extra cost for the thunderbolt interface.

  7. yann33 macrumors newbie

    Jul 12, 2013
    i booted from a LaCie Rugged 128GB SSD drive for a few months during the summer, which has both Thunderbolt and USB3 outputs.

    booting from USB3, i frequently encountered hanging and system freezes which forced me to reboot. no issues whatsoever while booting from Thunderbolt. Speedtest showed slightly better read and write speeds over USB3, but the system freezes were a non-starter. Might have been due to El Cap betas though.
  8. thedeske macrumors 6502a

    Feb 17, 2013
    I think most agree - USB3 is great for storage or file access using photo edit and other apps, but Tbolt is much more reliable for an external sys boot.
    It's possible USBc will close the gap or be even better when it's widely available.
  9. MasterStewie thread starter macrumors newbie

    Dec 7, 2015
    I've didsome more research and apperently is the combination of a delock TB case with an Angelbird wrks for Mac ssd a very good combination. The SSD is 'faking' that it's an apple ssd and trim is standard enabled, even if it's external.

    I will try this combination although it will only be 256Gb instead of 512Gb.
  10. matreya macrumors 65816


    Nov 14, 2009
    Why bother? You can turn on TRIM for all SSDs with a simple terminal command.
  11. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    There is nothing really wrong with the Angelbird drive, but I agree with matreya. There is no reason to pay more for that drive just for native TRIM support. That drive is $159 and a Samsung 850 EVO is $81.... I'm not seeing the value.

    Since the latest version of Yosemite and now El Capitan you can natively enable TRIM on a third party SSD by running the command below in Terminal.

    sudo trimforce enable
  12. DeltaMac macrumors G3


    Jul 30, 2003
    Not quite...
    USB does not support the trim commands.
  13. Fishrrman macrumors Pentium


    Feb 20, 2009
    I've been booting and running my late-2012 Mac Mini using a USB3/SATA docking station with an SSD for three years now.

    NO problems booting -- runs smooth and fast.
    NO problems with TRIM -- never have used it and SSD runs as fast as when new (have tried with 2 different SSD's, same results).

    In my opinion, TRIM really doesn't matter much at all.
    In my opinion, USB3 will be as fast as thunderbolt, insofar as an "external booter" is concerned.
  14. Richdmoore macrumors 68000


    Jul 24, 2007
    Troutdale, OR
    There are two issues:

    The angelbird drive "fakes" it's identification to say it is a genuine apple drive. Since the last (I think) Yosemite update, and every El Capitan version, after using the trimforce command any ssd will use trim, so no need anymore to pay the premium for the angelbird drive vs another brand.

    The second issue is thunderbolt vs USB. You are correct USB does not support trim. This is true no matter if it is a real apple SSD, an angelbird SSD, or any other SSD drive in any USB case.

    Thunderbolt drives enclosures/cables are much more expensive than USB 3. You will pay a premium, but trim will work with thunderbolt.

    Is trim needed for the newest SSD drives vs the native internal garbage collection? There is a healthy debate on the Internet, no clear answer.

    Since I had to use a thunderbolt SSD drive anyway as my Mac only had thunderbolt and USB 2, I turned on trim via the trimforce command.
  15. MasterStewie thread starter macrumors newbie

    Dec 7, 2015
    A lot of valuable answers. Thanks guys!

    Trim needed or not is a big question. I believe that GC can do already a lot and TRIM is helpfull to do it better with less deleted data copied.
    For Trim I've read the wrong information, I was thinking that you need to disable Kext for TRIM but this isn't needed anymore.

    At this moment I'm thinking about TB with samsung 850 pro 256/512GB but even the 850 evo would be good enough. That it will die earlier isn't a problem as the lifetime will be larger than the usetime (for me). (great price difference).
    I checked my 1.5 year old 840 evo 512GB SSD in my laptop (only PC in house) and I've written 2.32TB to it, this is nothing for a SSD these days. TB for stability and I believe it is a more directer connection than USB.

    Raw speed doesn't say anything for me, overal real performance and stablity are much more important for me. At the end it's just a consumer PC and not a PC that needs to perform heavy tasks.

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