SSD limitations due to SATA II in 2010 iMac?

Discussion in 'iMac' started by Florida Gator, Jul 4, 2011.

  1. Florida Gator macrumors regular

    Feb 26, 2004
    I am considering getting a refurbished 2010 iMac to save some money and plan to put an SSD in it. To my knowledge, the 2010 iMacs only had SATA II, and thus, are not able to run at 6Gb/s like a lot of these new SATA III SSDs are capable of.

    I'm very uninformed about this topic and couldn't find the answer I wanted via search. So my question is, how much does this limit performance? Would an OWC 6G SSD simply saturate the entire 3Gb/s on SATA II? Would that be my bottleneck? Or are the performance gains by SATA III SSDs simply insignificant at this moment? Are these SATA III SSDs actually using that 6Gb/s?

    Thanks in advance.
  2. Fried Chicken macrumors 6502

    Fried Chicken

    Jun 11, 2011
    Those measurements are in bits/s. 8 bits = 1 byte.

    SSDs for some reason give their measures in bytes/s.

    a 3 gb (gigabit) per second connection is about 375 MB (megabytes) per second connection. (rough calculation)

    So if you don't want to saturate your connection, go with an SSD that has a sequential read/write at around 375 MB/s (this is fast).
    Anything faster would saturate your connection.

    But understand, the real advantage of an SSD is low latency (time to find files), and incredible random read/write performance (reading a file, then jumping to a file at a different "location" and reading that file)

    So even if you bought a high end SSD that would saturate a SATA II connection, if it offers higher random read/write performance than a lower end SSD, then you would still get an advantage/boost in performance.
  3. Florida Gator thread starter macrumors regular

    Feb 26, 2004
    Thanks for the response. As far as practicality, has anybody here used a SATA II SSD and then moved to a SATA III SSD? Any noticeable comparison to performance in day to day tasks? If so, how much?
  4. philipma1957 macrumors 603


    Apr 13, 2010
    Howell, New Jersey
    look into a sata II ssd for that machine. while having a fast ssd is nice having an ssd that works is more important. intel has 320 series out and samsung has 470 series out both are fast not fastest they key is they work.\-_-20-147-064-_-Product

    any of the three above are a better choice in a 2010 iMac.

    Now if you have a sata III connection the owc is better.

    New macbook pros and iMacs (2011) have sata III

    If you google a lot you will find different info and opinions about ssds. What is good or slow or breaks a lot etc.

    You will not find many people that say the intel series 320 or the samsung series 470 bricked.
  5. Florida Gator thread starter macrumors regular

    Feb 26, 2004
    I'm moreseo trying to decide between the 2010 refurbished 27" iMac and a 2011 Mac Mini (presumably the same guts as the 13") and a 27" Dell monitor. SSDs in both. So if SATA3 is indeed noticeably faster, I might be inclined to get the Mini.
  6. alust2013 macrumors 601


    Feb 6, 2010
    On the fence
    You're probably going to notice that the performance gains aren't too crazy with the 6Gb/s SSDs, and stability is much worse. The SATA II models are already fast enough that that little bit faster isn't too noticeable comparatively. 375MB/s is really fast, so I wouldn't worry at all about sluggishness.
  7. Hellhammer Moderator


    Staff Member

    Dec 10, 2008
    SATA uses 8b/10b encoding scheme (8 bits are transferred as 10 bits) so there is a 20% overhead. That is why SATA 3Gb/s maxes out at 300MB/s, although in real world that is ~285MB/s due to additional overheads like latency.
  8. smayer97 macrumors newbie

    May 24, 2010

    Think again. See this re "Intel 320"
  9. smayer97 macrumors newbie

    May 24, 2010
    That is why the fastest SATA II 3G SSDs are rated at about 275-285MB/s.

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