Resolved EXTERNAL SSD SPEEDS

Discussion in 'macOS' started by Trips, Apr 15, 2019.

  1. Trips macrumors newbie

    Trips

    Joined:
    Mar 19, 2019
    Location:
    ATL, GA
    #1
    Okay so.. In a nutshell I'm curious about factors that could impact External SSD speeds over USB3/3.1. I'm posting this here specifically since my experiences have ranged between Sierra, HS, and Mojave, with various USB3 and USB3.1 enclosures, and two different Samsung SSDs, an 840 Pro 256GB, and a brand new 860 Evo 1TB, and two different macs.

    Im hitting what I can only describe as a "Speedwall" when testing via BlackMagic, or even testing actual file transfers monitoring the R/W speeds between drives with iStat. My Read speed wall is 430mbps, and write speed wall is 420mbps. Doesn't seem to matter which drive or enclosure I used (I have several) nor which device I test on (2018 Mini or 2013 MBP, both currently running Mojave). I can not seem to go above those speeds. I had the same speed limitations with the 840 Pro on the Macbook pro in Sierra and HS, HFS+ and now w/ APFS.

    Its super odd to me. I can't seem to get the write speeds samsung reports when using SSD externally on MacOS. That same 840 Pro on windows hits over 560mbps. Even this brand new 860 Evo 1TB I just received today, when plugged into a USB3.1 Gen2 enclosure maxes out at 430mbps/420mbps, whether I use HFS+ or APFS.

    Any ideas as to what could be causing this?
    --- Post Merged, Apr 15, 2019 ---
    Here are two benchmarks results tested just now. The first is the new 1TB 860 EVO, the second is the 256GB 840 PRO. Both seem to hit the same wall as I explained above.

    The 1TB is in a Vantec USB 3.1 gen2 enclosure. The 256GB is in a Sabrent USB3.0 enclosure. But Ive tried either SSD in either enclosure, same results. I've tried other enclosures I have as well, same results. All my enclosures are USB3.0, with the one Vantec being 3.1 gen2, but that shouldn't even matter as USB3 should be enough to support R/W's at the suggested Samsung speeds 550/520, no?

    I'm wracking my brain with this! Any help would be appreciated!
    Thanks in advance.
     

    Attached Files:

  2. Fishrrman macrumors P6

    Fishrrman

    Joined:
    Feb 20, 2009
    #2
    USB3.1 gen1 is going to "top out" about 430mbps -- just as you have discovered.

    If you want "faster", there are two choices:

    First choice:
    USB3.1 gen2 -- about twice as fast as gen1, should top out around 900mbps.
    However -- there are few (any?) "ready-to-go" USB3.1 gen2 drives out there.
    You pretty much have to "build them yourself" right now.
    Best solution is to get a USB3.1 gen2 nvme enclosure, and an nvme "blade SSD", and put them together. Costs a little more, for double the speed.

    Second choice:
    thunderbolt3 -- VERY fast, as fast as an internal SSD, 2,000-2,500mbps or higher.
    Samsung X5 is a "pre-built" drive that can deliver.
    BUT... EXPENSIVE.

    How much speed do you want?
    How much moola do you have?
     
  3. dwig macrumors 6502a

    Joined:
    Jan 4, 2015
    Location:
    Key West FL
    #3
    ... and with either of Fishrrman's good suggested options, you need to be certain that the cable used supports the data protocol. Not all cables support all speeds.

    Also, the port on the computer can be a limiting factor. The Mac Mini 2018's USB-A ports will only support USB 3.0 speeds. To get the USB 3.1gen2 (aka USB 3.2gen2) speeds you need to connect to the USB-C ports which support up to USB 3.1gen2 and TB3.
     
  4. Trips thread starter macrumors newbie

    Trips

    Joined:
    Mar 19, 2019
    Location:
    ATL, GA
    #4
    Okay, and what if I've covered all of those bases already? lol

    In the original post I mention having tried several USB3 enclosures as well as a USB3.1 gen2 enclosure.
    This 3.1 Gen2 Enclosure which is connected directly to USBC, not USB-A 3.0 port.
    I also have this enclosure, this one and even this quick connector all via USB3. I've used all of those on Win10, and have no issues hitting the Samsung suggested speeds of 500-550mbps over USB3.

    SO, It seems odd to me that this "speedwall" I appear to be hitting with either SSD and ANY of these enclosures is the same 430mbps on MacOS. I would expect to be able to get over 500mbps with either SSD on the Vantec 3.1 gen2 enclosure at least. Which brings me back to my original question, what else could be going on?

    I am prepared to purchase and try some other 3.1 gen2 enclosures to try getting the performance these SSDs are capable of. I mean we're are talking a good 20% performance loss. I'm just suspicious that there may be some other underlying issue here, and I'm not certain throwing money at more 3.1 gen2 enclosures would even make a difference, hence my post.
     
  5. Fishrrman, Apr 16, 2019
    Last edited: Apr 16, 2019

    Fishrrman macrumors P6

    Fishrrman

    Joined:
    Feb 20, 2009
    #5
  6. Trips thread starter macrumors newbie

    Trips

    Joined:
    Mar 19, 2019
    Location:
    ATL, GA
    #6
    First.. that enclosure you posted would totally bottleneck the NVMe SSDs they suggest work with it. Why put a 970 EVO capable of over 3000mbps into an enclosure only capable of 1/3rd that speed if we are just throwing money at the problem? LOL
    If I was going the NVMe route I'd do Thunderbolt 3 or even an Express 4N2 and add more NVMe's as I needed.

    The question I'm asking isn't how to get the fastest SSD. I know how to do that. The question is why are the current ones (which should be fine for my needs) not performing to their full potential, across the board.

    And thanks! That Vantec is super nifty. BUT, its 3.1 gen2 so it should be fine, yeah?
    So you mentioned its limited by the drives going in it. But Ive stuck two different Samsung SSDs that I know are capable of over 500mbps. I've seen them do it on Windows and moreover they were able to do so in the 3.0 enclosures I listed above.

    So the question remains.
     
  7. GumaRodak macrumors newbie

    Joined:
    Mar 14, 2015
    #7
    You can try sandisc 900 extreme external ssd with speeds around 800
     
  8. Trips thread starter macrumors newbie

    Trips

    Joined:
    Mar 19, 2019
    Location:
    ATL, GA
    #8
    Well it appears I've been lied too! It seems that despite the specs of that "nifty" Vantec 3.1 gen2 enclosure listed on Amazon, they are being less than honest about it being gen2, or at least the molded cable attached to the controller anyway. So if you're looking for an inexpensive 3.1 gen2 enclosure, I suggest you steer clear of the Vantec USB3.1 Gen2 (CB-STC31-2PB) on Amazon!

    I instead purchased a MediaSonic HDM-U31C and the speeds are much, much better and closer to Samsung Spec. [See attached Screenshot]

    CONCLUSION:
    I still find it very odd that a PC I built in 2014 is able to hit 500-550mbps via regular old USB3.0 enclosures on Windows 10, but for whatever reason I can't achieve the same in MacOS Mojave on a brand new 6 core 2018 Mac Mini using the exact same SSDs and enclosures. I mean, I use my Mac for work, the Win10 PC is a glorified Plex server at this point!

    As a result, I still feel there is some deficiency happening in MacOS. APFS maybe? Some other bottleneck? I've no clue. But at least for now, I'm able to get the speeds I was looking for despite having to use 3.1 Gen2 enclosures with more headroom (5Gbps vs 10Gbps). Interesting. Confounding even! o_O
     

    Attached Files:

Share This Page

7 April 15, 2019