What does it take at this point to bottleneck SATA II?

Discussion in 'Mac Pro' started by Ravich, Feb 24, 2011.

  1. Ravich macrumors 6502a

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    #1
    I heard someone say (audio production related) that running a certain sample library on an SSD through SATA III produces significantly better results compared to SATA II.


    Why would this be? As far as I can tell, the best SSDs on the market are barely surpassing SATA II's bandwidth, but maybe I'm missing something.
     
  2. derbothaus macrumors 601

    derbothaus

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    #2
    There is alway management overhead. A 300Gb/s pipe will most likely net you around 265-285 MB/s. So anything that can sustain those numbers would see a benefit from going to SATA lll 6Gb. Sandforce-2500 controllers are gearing up with advertised 500MB/s r/w.
     
  3. Ravich thread starter macrumors 6502a

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    #3
    Ouch. Guess that's a bit of a disadvantage for current Mac Pro owners. What is the bandwidth of the PCI slots on the Mac Pro? Two x4 slots and a single x16 slot, right?
     
  4. mdgm macrumors 6502a

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    #4
    One thing you should note is that there are both sequential and random write benchmarks. The sequential numbers that are high tend to get quoted. These are generated using test files designed to give fast speeds.

    Random writes where stuff happens pseudo-randomly tend to be much lower.

    Real world usage would tend to give performance inbetween random and sequential write benchmarks and would depend on a variety of factors (e.g. copying lots of small files, copying one large file, the nature of the files involved etc.).

    So a SATA III SSD is still going to be better than a SATA II SSD even when using SATA II.

    Of course to get the full benefit of SATA III you would need to be using SATA III. We should see SATA III in the next Mac Pro refresh which will hopefully involve the use of Sandy Bridge Xeons due for release late this year. So we may not see the Mac Pro updated till early next year
     
  5. derbothaus macrumors 601

    derbothaus

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    #5
    I guess but then again p67 was not out and not for Xeons. PCI slots are there if you really need USB 3.0 or eSATA 6Gb. Also there are only like 2 or 3 SSD's that can saturate a 3Gb bus. So for owners of those 3 SSD's are pretty bummed they can't get 20MB/s more out of their drive. All others it is a non issue.
    The 2010 has 4x 16x slots with ability to slot 2 at 16x, does not matter which slots the rest get 4x if they are all slotted.
     
  6. Ravich thread starter macrumors 6502a

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    #6
    What about the 2009 then? What does x4 or x16 translate to in terms of Gb/sec?
     
  7. Transporteur macrumors 68030

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    #7
  8. Ravich thread starter macrumors 6502a

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    #8
    Oh my. That is quite a bit of bandwidth. So hypothetically then, what would be the best way of getting the maximum out of a x16 slot? It would take, like, 6 lightpeak interfaces to saturate that bandwidth, right?
     

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