What am I doing wrong with my SSD setup? 110MB/s read/write

Discussion in 'MacBook Pro' started by eeclipse16, Jan 2, 2013.

  1. eeclipse16, Jan 2, 2013
    Last edited: Jan 2, 2013

    eeclipse16 macrumors member

    Jun 19, 2012
    Am I doing something wrong with my external SSD setup? I thought it would be faster then it is right now. Im not to knowledgeable about SATA I, II, III and eSATA but im thinking I might have got the wrong (slower) enclosure. I know you never get to close to the manufacturers specs but im 5x slower on the read and 3.5x slower on the write. I want to stick with USB 3.0 because thunderbolt setup after enclosure and cable would be almost the price of another SSD.

    Here is the enclosure im using


    Take advantage of the lightening speed of USB 3.0 to quickly transfer files up to 5 Gbps! Connect any 2.5″ Serial ATA (SATA) or SATA II Hard Drive to your computer through an available USB 3.0 port on your desktop or laptop. It is constructed from durable aluminum, to ensure heat dissipation. Transfer data quickly and easily, anywhere, with this great external hard drive case. This enclosure allows you to connect your SATA HDD to USB 1.1, 2.0. or 3.0.

    With this Samsung SSD


    840 PRO Series
    Capacity: 128GB
    Sequential Read Speed: Up to 530MB/s
    Sequential Write Speed: Up to 390MB/s

    Attached Files:

  2. eeclipse16 thread starter macrumors member

    Jun 19, 2012
  3. spartacvs macrumors member

    Jan 1, 2013
    Just guessing here but that enclosure looks like it doesn't support SATA III only I and II. Another reason is because you're using it as an external drive and not as an internal drive.
  4. eeclipse16 thread starter macrumors member

    Jun 19, 2012
    Thank you for your reply and that's what my uneducated guess was something to do with the sata. As for the external drive part I was expecting that but I have seen some people getting in the 250 mb/s range and was hoping to be around there also.
  5. eeclipse16 thread starter macrumors member

    Jun 19, 2012
  6. w00t951 macrumors 68000


    Jan 6, 2009
    Pittsburgh, PA
    No idea what's causing it, if it's not the enclosure. Right now, it looks like professional and consumer USB 3.0 storage solutions aren't coming anywhere near the 500-650MB/s advertised speeds of the new USB spec.

    But that Samsung 840 Pro should be redlining the benchmark utility. It's currently the fastest SSD money can buy.

    By the way, running repeatedly benchmarks on your SSD isn't very healthy for it.
  7. eeclipse16 thread starter macrumors member

    Jun 19, 2012
    Anyone have any idea what I'm doing wrong?

    If I end up keeping it all just return the SIIG and go back to the Sabrent because its $25 cheaper and does the same speed.
  8. scenox macrumors member

    Oct 20, 2012
    Try to use a different USB cable. The USB 3.0 spec considers it reasonable to achieve 3.2 Gbit/s (400 MB/s) in practice.
  9. simsaladimbamba

    Nov 28, 2010
    Normally modern SSDs have a theoretical write/read limit of 10,000 to 100,000 cycles (P/E cycles), meaning if you had a 64 GB SSD and its cycle limit would be 10,000, you would have to write 625 TB to it, which would be 351 GB per day everyday for the next five years. Assuming those numbers vary and it would only be a tenth of that, it would still mean 35 GB per day for five years, which under normal usage no average computer consumer does, not even with temporary files.
  10. mandy2tom macrumors newbie

    Jun 29, 2014
    SSD slow fixed

    I had the same problem on 27" iMac fusion with my Lacie 256 SSD thunderbolt and usb3

    OSX 10.9.3 disk utility wont let you zero out SSD UNLESS you first encrypt the drive then it will, and that fixed corrupted SSD

    my write speeds had dropped to 21mb/sec

    now i'm back to 300+mb/sec write time, and around 400+mb/sec read
    I'm pretty sure I corrupted it when I accidentally unplugged it while booted from it
    anyway all good now!

    So zeroing out the drive fixed mine.

    just reformatting wont work, you have to write zero's to the drive

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