Ssd as external USB boot drive?

Discussion in 'Mac mini' started by rnelan7, Jun 7, 2010.

  1. rnelan7 macrumors 6502

    rnelan7

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    #1
    From reading various threads it seems as if replacing the stock hdd with an sdd will void the warranty. I was wondering how practical it was to buy an external enclosure for an ssd and connect it to the mini via USB and boot off of it? Theoritically it should still be as fast because USB can reach 480mb speed while an intel x 25m tops off around 275. Any thoughts or advice?
     
  2. Hellhammer Moderator

    Hellhammer

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    #2
    USB 2.0 tops out at 480Mbit/s i.e. 60MByte/s. There is huge difference between small b and big B. So Intel SSD tops out at 275MB/s (2200Mbit/s) which is more than four times faster than USB 2.0's maximum speed.

    Not worth it, your internal is faster
     
  3. rnelan7 thread starter macrumors 6502

    rnelan7

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    #3
    Thanks for the clarification, it's a no go then!
     
  4. Sensamic macrumors 68030

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    #4
    I use an external SSD as boot drive and it is definitely worth it if you dont want to open up your mac mini. I use it on the imac and couldnt be happier. Everything works perfectly. The OS and apps boot even faster. Sustained transfer rates are exactly the same as with the internal hard drive. And you get a completely silent machine.
     
  5. gianly1985 macrumors 6502a

    gianly1985

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  6. flatfoot macrumors 65816

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    #6
    Yep, don't bother with crappy USB transfer rates.
     
  7. Heilage macrumors 68030

    Heilage

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    #7
    Also, it is worth noting that USB speeds (480Mbit/s) is purely theoretical AND burst speeds, not constants, and does not offer room for overhead. In reality, you'll never get above 20-30MB/s on a USB unit.

    FireWire 800 runs circles around USB, both in theory and real life.
     
  8. Hellhammer Moderator

    Hellhammer

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    #8
    But even FW800 is over 3 times slower than the fastest SSDs...
     
  9. Heilage macrumors 68030

    Heilage

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    #9
    Ofcourse. SSD would only be remotely useful in eSATA configuration.
     
  10. spinnerlys Guest

    spinnerlys

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    #10
    Even though I prefer FW since 1999, I can reach up to 35MB/s constant transfer speed over USB 2.0 with my 2.5" external S-ATA HDDs.
     
  11. Sensamic macrumors 68030

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    #11
    I use my SSD via FW800. I knew it was going to be slower than SATA but I didnt want to open my imac. What I cared about was to have a silent imac, and I finally got it. I didnt care about the increased speed of SSDs, but in the future I might put the SSD inside the imac or the next computer I buy. Right now Im very very happy.
     
  12. AppliedMicro macrumors 6502a

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    Aug 17, 2008
    #12
    While many mechanical hard drives achieve higher maximum transfer rates than FW800, this is not the case with average or minimum. An SSD continously saturating the FW800 interface might very well be faster than a mechanical drive. Also, you should benefit from lower access times / latency.
     
  13. Heilage macrumors 68030

    Heilage

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    #13
    While that is true, booting from an external SSD is a waste of money if you ask me. An SSD can saturate a 1,5Gbps S-ATA controller, that speaks for itself.
     
  14. itickings macrumors 6502a

    itickings

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    #14
    You are of course entitled to the "waste of money" opinion, but I have to strongly disagree with the 1.5Gbps speaking for itself. For a drive hosting the operating system and applications, access time and latency is of great importance as well. For a somewhat broken car analogy; having a car with a very high top speed and slow acceleration isn't always as interesting as having a car with a reasonable top speed and quick acceleration. It depends on how it is going to be used.

    Sure, it is no doubt better to boot from the SSD connected to SATA than FW800, I don't question that. But if replacing the internal drive isn't an option, a SSD over FW800 can still be a worthwhile upgrade in some situations. For example, check out the random read/write numbers from my old post.

    Just because the full potential of the SSD isn't reached, it doesn't mean that it still isn't significantly faster than the alternative.
     

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