SSD with 3 GB/s data cable - is this ok?

Discussion in 'iMac' started by Ne0the1, Feb 17, 2016.

  1. Ne0the1 macrumors member

    Joined:
    Jan 5, 2013
    #1
    Hello all,

    I will be installing an additional SSD in my iMac. Will a 3GB/s data cable be sufficient?

    I think the read and write speeds will be roughly 500MB/s.

    I wasn't sure if I would needa 6GB/s cable. Just confirming that 3GB/s cable will be fine and won't slow down any data transfer?
     
  2. bent christian Suspended

    bent christian

    Joined:
    Nov 5, 2015
    #2
    SATA II won't give you 500MB/sec. SATA II write speeds will come in in the 280 range. To take full advantage of the SSD, you will need SATA III.

    http://kb.sandisk.com/app/answers/detail/a_id/8142/~/difference-between-sata-i,-sata-ii-and-sata-iii

    What year is the machine? It is possible to get close to 500MB/sec (close enough not to notice the difference) by booting externally through USB 3.
     
  3. Ne0the1 thread starter macrumors member

    Joined:
    Jan 5, 2013
    #3
    Hi,

    Thakns or your reply.

    My iMac is Mid 2011. So I would need Sata III to get the most out of the SSD?

    I put an SSD in my Macbook Pro Early 2011, and I get 500MB/s but that was using the existing cable. So I assume the existing cable in my Macbook Pro must be Sata III?
     
  4. bent christian Suspended

    bent christian

    Joined:
    Nov 5, 2015
    #4
    Yes.

    You may be able to get close using a Thunderbolt to USB 3 adapter. Check this thread. You won't have to open the machine.

    Lately, I have been booting externally using USB 3. Write speeds are 395MB/sec and reads are 429MB/sec. You may not notice the 100MB/sec difference in real word use.
     
  5. Ne0the1 thread starter macrumors member

    Joined:
    Jan 5, 2013
    #5
    Thanks for your reply.

    I will be putting the SSD in the iMac, I don't want to boot from an external drive.

    I prefer it to be internal. So it's best I get the 6GB/s cable then.

    Why does my MacBook Pro Early 2011 achieve 500MB/s both read and write. I replacd the HD so the existing cable must be 6GB/s?
     
  6. bent christian Suspended

    bent christian

    Joined:
    Nov 5, 2015
    #6
    I think Apple got SATA III in 2011. The optical bay might be SATA II, so don't put the drive there.
     
  7. Ne0the1 thread starter macrumors member

    Joined:
    Jan 5, 2013
    #7
    I won't be replacing anything. There are additional ports on the logic board (one for power, one for data).

    Screen Shot 2016-02-17 at 21.26.56.png

    Does anyone know what speed this supports?
     
  8. pdafan macrumors member

    Joined:
    Aug 2, 2011
    #8
    Done it before. Just get the 6GB SATA3 data cable and the right SATA power cable.
    Follow iFixit guide.
    https://www.ifixit.com/Guide/Installing+iMac+Intel+27-Inch+EMC+2429+Dual+Hard+Drive+Kit/7575

    You will get SATA3 speed.
     
  9. Ne0the1 thread starter macrumors member

    Joined:
    Jan 5, 2013
    #9
    Thanks, this is similar to the guide I saw already. As I have a 21.5" iMac.

    Glad the logic board supports Sata 3 from these ports :)

    Already ordered the cables. Did you need the right angled sata cable, or will a regular end be ok?
     

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