External HDD (With enclosure) for MBP (HELP!)

Discussion in 'Buying Tips and Advice' started by Kaioken!, Nov 11, 2007.

  1. Kaioken! macrumors newbie

    Nov 7, 2007
    Hey everyone i need some purchasing advice with regaurds to external HDDs.

    Im interested in getting a speed demon SATA HDD and putting it into an enclosure and using it as an external for my recently purchased MBP, the HDD im looking at will probably be 10K rpm, good for logic studio / pro tools ectect. :D

    Though, im not sure about externals though, what are the drawbacks? Does going through USB 2.0 slow down the transfer rates? Does having Firewire 800 available make a difference to this speed? Whats the best enclosure to buy and am i stupid for even asking?

    I guess my question is; can i run a fast Hard Drive externally, in a HD enclosure? And can it be faster than my internal 7200RPM drive? Or is its speed going to be affected by USB 2.0 or Firewire?

    Help is appreciated, cause i seriously don't know the lowdown on externals and how they run.

  2. admiraldennis macrumors regular

    Aug 19, 2002
    Boston, MA
    Popular interfaces and their theoretical maximums (reality will be less):
    -FireWire 400: 400MB/sec
    -USB 2.0: 480MB/sec
    -FireWire 800: 800MB/sec
    -SATA-150: 1.5Gb/sec
    -SATA-300: 3.0Gb/sec

    USB has higher CPU overhead than Firewire and SATA. SATA and USB are 'shared bandwidth' busses -- multiple devices operating on the same bus will be sharing the total bandwidth.

    The average latest-gen 7200 RPM drive can just about fully saturate SATA-150 in the real world.

    Conclusions: no external FireWire/USB drive will be as 'fast', bandwidth-wise, as your internal drive. A 'speedy' drive with a high RPM may still provide benefit, as high-RPM increases the performance of bandwidth-independent processes such as random seeking and simultaneous read/writes. Bandwidth will, however, be mildly to substantially constrained by a slow bus.

    If you truly require the maximum possible speed from an external device, your best bet would be to buy an eSATA card for your MBP.

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