SSD boot drives that don't degrade with time

Discussion in 'iMac' started by bent christian, Sep 15, 2016.

  1. bent christian Suspended

    bent christian

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    #1
    I boot externally via USB 3 using a Samsung Pro. Write speeds were great for a while (~420MB/Sec), but now benchmarking puts me at around 170MB/Sec, sometimes as low as 90MB/Sec. Sometimes as high as ~212MB/Sec, but never has high as it should be. Read speeds are a consistent ~430MB/Sec, so I know USAP is functioning and the speed is available on the bus. It seems like an issue with the drive. My research shows Samsung being called out and that this is a known issue. Customer Service claims the drive is designed to be used with TRIM and that I can send to drive in for inspection under warranty. Not having another SSD in the house means that my machine is put out of commission for awhile. I am debating the merits of sending the drive in, as it still operates very snappily despite this very low benchmarking. Maybe the low write speeds don't matter for my uses? I don't know.

    Have others used SSDs for six months or more through USB 3 and not found this degradation?

    I am wondering if I should have gone with the inexpensive Transcend StoreJet Thunderbolt drive just for the TRIM function. I was under the impression TRIM was not really necessary, but maybe it is? Maybe with only some manufactured drives and not others?
     
  2. danielwsmithee macrumors 6502a

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    #2
    Have you enabled TRIM using trimforce?

    http://www.howtogeek.com/222077/how-to-enable-trim-for-third-party-ssds-on-mac-os-x/

    I'm not even sure if it will work over USB...
     
  3. bent christian, Sep 15, 2016
    Last edited: Sep 15, 2016

    bent christian thread starter Suspended

    bent christian

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    #3
    There is no analogue to TRIM for USB. ;(

    People have been insisting that TRIM is unnecessary for many of the high-quality SSDs produced today - Garbage Collection is enough. I am wondering if that is incorrect information. My old Thinkpad running Windows (with TRIM) benchmarks at ~270MB/Sec on a SATA II bus, using the lesser-quality EVO 850 drive. I have had that drive installed for much longer, yet speeds are more consistent with where the drive should be. I don't know if the controller in the Pro is defective, or if this is the result of not having TRIM available.
     
  4. danielwsmithee macrumors 6502a

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    #4
    Different controllers/firmware handles things like a wear leveling differently. So yes you will probably see a difference between controllers etc. The other piece is a how much free space is available. Some drives use over-provisioning to avoid performance degradation. You can get the same by leaving lots for free space on your drive.
     
  5. bent christian thread starter Suspended

    bent christian

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    #5
    Yes, I understand all of that. I have researched the issue extensively. Free space is not the problem. I have about 144GB free of 200GB formatted. The rest (~40GB) I left as unallocated, 256GB total. This drive is only a boot drive. I have a couple of games kept there, but otherwise the only data written is what is necessary for the operating system. Caches and scratch disks for Illustrator, Photoshop, and Lightroom are sent to another disk. I don't know what else I can do to minimize the use of this drive. Pretty much everything is directed elsewhere. Still crappy writing benchmarks.

    What are others' experiences with USB 3 booting, longterm?
     
  6. simonsi macrumors 601

    simonsi

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    #6
    If its only a boot drive then the varying and low write speed won't affect your user experience very much.
     
  7. Samuelsan2001 macrumors 604

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    Oct 24, 2013
    #7
    It's the issue with using a USB 3 SSD and no trim support, a lot of modern ssd's claim that trim is not needed this seems to be an outright lie as far as I can tell.

    If you have a spare Mac with a SATA connected HDD, maybe an old MacBook or one you can borrow you can insert it in that force trim and then It'll be good for another 6 months before needing it again.
     
  8. maflynn Moderator

    maflynn

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    #8
    Would a backup, reformat, and then reinstall also work?
     
  9. Samuelsan2001 macrumors 604

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    #9
    I think it would but having never tried it I'm loathe to suggest it.

    And of course it's a lot of wear on the SSD if it's unneeded.
     
  10. IngerMan macrumors 6502a

    IngerMan

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    #10
    Given Trim is not supported on USB, is it supported using Thunderbolt? Just curious.
     
  11. danielwsmithee macrumors 6502a

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    #11
    Thunderbolt is functionally equivalent to being connected to an internal SATA port.
     
  12. Fishrrman macrumors G4

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    #12
    bent wrote above:
    "I boot externally via USB 3 using a Samsung Pro. Write speeds were great for a while (~420MB/Sec), but now benchmarking puts me at around 170MB/Sec, sometimes as low as 90MB/Sec. Sometimes as high as ~212MB/Sec, but never has high as it should be."

    Could be the drive, could be the enclosure.
    Also, HOW FULL is your SSD?

    I picked up a Crucial M500 back in mid-2014, which I use to boot and run my late-2012 Mac Mini (it sits in a plugable.com "lay-flat" USB3/SATA dock).

    Tested when new, it gave me reads of 431mbps and writes of 259mbps.

    Tested a few moments ago, it gives reads of 431mbps and writes of 236mbps.

    Of course, TRIM has never been enabled.
    But it still "runs like new" on my setup.

    I'm probably one of the few members of this forum who DOES NOT recommend Samsung drives as "a first choice".
    I prefer Crucial or Sandisk.
    And even then, I don't use their "high-end" models.

    I also DO NOT recommend the use of thunderbolt.
    As you can see above, my use of USB3 above (with the appropriate enclosure) has resulted in only a small decrease of write speeds, which is un-noticeable during normal usage.

    I also recommend something that NO ONE, anywhere else, will suggest:
    That, periodically, you run an optimizer or defragger on the SSD drive, just as you would on a platter-based hard drive.
    I can almost hear the cries of those who will jump on me for having made this statement (look out, here they come!)

    But again, look at my results above.
     
  13. Weaselboy Moderator

    Weaselboy

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    #13
    I would about bet money that TRIM is your issue, particularly given that this is only impacting write speeds.

    I can't think of forum posts specifically with no TRIM over USB causing this, but I have seen a lot of posts with internal third party SSDs run without TRIM causing this write slowdown, and a quick TRIM run with "fsck -fy" in Terminal immediately restores write speeds.

    I think the only solution here is for you to somehow run TRIM on that drive. Do you have access to maybe a Mac portable or Thunderbolt enclosure where you could pop that drive in and run TRIM once?
    --- Post Merged, Sep 16, 2016 ---
    Nope... that won't work if the setup (like this USB connection) does not support TRIM.
     
  14. bent christian, Sep 16, 2016
    Last edited: Sep 16, 2016

    bent christian thread starter Suspended

    bent christian

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    #14
    Yeah, I haven't noticed the system slowing down at all. Adobe applications open in just a few seconds. Boot time is like 15-20 seconds from button press to login screen. Totally fine for my home use. I have only been researching the issue, because I want to get the most of my equipment. If there is genuinely something wrong with the SSD unit, I would like to get it repaired. I am leaning toward the controller being fine, Samsung SSDs need TRIM to function properly. This is counter to what I have read here and elsewhere n the 'Net.

    I don't. We have a MBP, but it's a 2013 - not easily taken apart and uses a blade, anyway.

    This is one of the first things I tried. Speeds reduced shortly afterward.

    The drive is over 1/3 full, but far less than half full. There is plenty of free space. The only data written is that used by the OS and maybe some apps. All caches, scratch disks, etc. have been directed to another drive (internal 1TB Fusion).

    Your experience is interesting, but I don't think I am going to sink any more money into experimenting. The system is fine for now. When warranty expires I will pay someone $200 to install internally through the SATA port or go Thunderbolt.


    I have read some conflicting info on regarding over provisioning:

    Is the proper way to provide over provisioning for an OSX external boot drive like this to leave a portion as RAW (unallocated), or can it be formatted and left as empty of data?

    I have read online that OP space can be (should be?) unallocated, but the Magician software in my other Windows machine tells me that leaving RAW sectors can lead to data corruption. I have no way to create an over provisioning area through the Samsung software, as it is not made for the Mac platform. Do people make a full HFS+ format and just go with that? Right now I have ~40GB unallocated of 256GB to be used for OP. I don't know if this is the correct way of doing it.
     
  15. Weaselboy Moderator

    Weaselboy

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    #15
    According to this article, the Pro has no space set aside for over provisioning, so that might make it more susceptible to the issue you are seeing.

    Yes... the correct way to allow some space for this would be to leave some space unformatted as you have.
     
  16. dimme macrumors 65816

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    #16
    Trim is supported with usb uasp enclosures. I was able to enable it on my 1mac via terminal running el captian
     
  17. Weaselboy Moderator

    Weaselboy

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    You are mistaken. Open Disk Utility and run First Aid on the drive and you will see TRIM is not run. If you run El Capitan DU First Aid on a TRIM supported external drive you will see the message ...Trimming unused blocks at the end of the text output in the little dropdown below the progress bar.

    I would be glad to be proven wrong here, but I have never seen anybody show they have had TRIM working over USB.
     
  18. bent christian thread starter Suspended

    bent christian

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    #18
    Yup. It is well-documented that TRIM is not supported over any variant of USB, only PCIe, SATA, and the like (Thunderbolt, etc).

    I think the Samsung drives do come with a small amount of OP. Formatted, my 256GB SSD registers as 230-something GB available. It definitely doesn't have the 10-15%+ recommended, but I think it has some.

    If leaving unallocated space is functionally the same as over provisioning, I don't understand why this drive would be more susceptible. Also, hardly any of the drive is being used and for just over six months. Probably just bad garbage collection. This brand should be flagged in the community for future user recommendations.
     
  19. dimme macrumors 65816

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    #19
    My mistake I was thinking of a thunderbolt drive I setup.
     
  20. maflynn Moderator

    maflynn

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    #20
    I'm running off a external USB as well, so I'll have to monitor the situation. Right now, its just the OS and I'm happy with the performance

    If it matters its a Samsung T3 external SSD
     
  21. Fishrrman macrumors G4

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    #21
    Weaselboy wrote:
    "I would be glad to be proven wrong here, but I have never seen anybody show they have had TRIM working over USB."

    Nor have I.
    But again -- in my personal experience -- the lack of TRIM seems to make very little difference at all in long-term performance. Essentially, NO difference.

    I realize that using drives from different manufacturers could alter the equation here.

    I'm wondering if the upcoming version of USB -- USB3.1 -- might change this?
    Is it "USB itself" that makes TRIM impossible, or ... only that the developers of the USB standards overlooked it?
     
  22. Weaselboy Moderator

    Weaselboy

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    #22
    My understanding of it is that TRIM is a ATA command and the USB bus will not carry ATA commands.
     
  23. definitive macrumors 68000

    definitive

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    #23
    Sometimes when more than half of the SSD is filled up, it can become slower.
     
  24. bent christian thread starter Suspended

    bent christian

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    #24
    That is not the problem here.
     

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