would it be faster to run a flash instead of pata?

Discussion in 'MacBook Air' started by one1, Mar 15, 2016.

  1. one1 macrumors 65816

    Joined:
    Jun 17, 2007
    Location:
    Chattanooga, TN
    #1
    I know my original Air has usb 2.0 ports so I'm thinking the 120gb pata drive in my air is still faster. I was going to use a micro 64gb flash that is so tiny it wouldn't even be visible and run Lion on it as my main drive to speed up the slow pata lag, but being 2.0 ports I'd guess it would be slower. Any opinions?

    Flash on 2.0 VS pata
     
  2. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #2
    If you have upgraded to a faster SSD than the original drive that came with that first Air, such as the PATA model that OWC sells - those are rated at up to 88 MBytes/s reads
    The USB 2.0 bus speed is 480 MBits/s or 60 MBytes/s. But, that is theoretical, and the USB bus usually won't provide near that speed, particularly for a booting system.
    So, booting through the USB bus on your MBAir will be slower than the PATA bus with SSD.
     
  3. cruisin macrumors 6502a

    cruisin

    Joined:
    Apr 1, 2014
    Location:
    Canada
    #3
    USB is slower than the internal connection, but a SSD has no lag and doesn't thrash when you try to do two things at once. So the top speed is lower (due to the USB connection), but it never slows down like hard drives do under load.

    Are you planning to use a micro SD card to run OSX? It won't last long as it doesn't have wear levelling like a full SSD does. And unless you buy an expensive one it will be slower than the original drive.
     
  4. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #4
    There's no card slot on the oldest generations of MBAir.
    A card reader would still be limited by the USB 2.0 speeds
     
  5. cruisin macrumors 6502a

    cruisin

    Joined:
    Apr 1, 2014
    Location:
    Canada
    #5
    And the speed is limited by the card used. A Samsung 64 GB micro SD card that claims up to 90 MB/s but according to one reviewer:
    • Sequential Read : 94.144 MB/s
    • Sequential Write : 87.389 MB/s
    • Random Read 512KB : 82.878 MB/s
    • Random Write 512KB : 12.736 MB/s
    http://www.amazon.com/Samsung-Plus-..._UL160_SR160,160_&refRID=01VYPMTPJ5M2XSP02CAF

    So it is good for all reads and but the writes need to be sequential, like a camera not an operating system. If the speeds are fine (and they will be less due to USB 2 compared to 3) then you still have to worry about how long the card will last.

    An builtin card reader still connects to USB internally.
     
  6. one1, Mar 24, 2016
    Last edited: Mar 24, 2016

    one1 thread starter macrumors 65816

    Joined:
    Jun 17, 2007
    Location:
    Chattanooga, TN
    #6
    Thank you for the replies. I was looking for a temp fix until my SSD comes in to try and speed me up past the pata/zif speeds of my upgraded 120gb hard drive. I figured being 2.0 it wouldn't be as fast.

    Now my issue is choosing the right SSD. I'm looking on ebay and I see them with the following specs below. My question is how fast 64MB/S is comparing to a fast hard drive such as 7200 rpm.

    I'm willing to lose storage space to increase performance.

    EDIT: I've attached a pic of my current upgraded HD.

    _______________________________________________

    Model

    KSD-ZF18.1-064MS

    General

    Form factor

    1.8"

    Capacity(GB)

    128GB

    interface

    ZIF44Pin(ATA7)

    Performance

    Average Access time

    0.2ms

    Sustained Read

    65MB/S

    Sustained Write

    40MB/S

    Random IOPS

    5.585

    Storage Media

    NAND Flash

    MLC-NAND Flash

    Power Consumption

    input Voltage

    3.3V or 5V+/_5%

    Idle

    0.5W

    Active

    1.5W

    Reliability& Endurance

    Write endurance

    80years@10GBytes write and erase per day at 32GB

    Read endurance

    unlimited

    Wear-Leveling Algorithm

    Dynamic and static wear-leveling

    Data Retention

    10years at 25¡æ

    MTBF

    1,000,000hours

    ECC

    Supports BCH ECC 8bits or 15bits in 512 bytes

    Bad Block Management

    Auto Bad Block Management in system
     

    Attached Files:

  7. cruisin macrumors 6502a

    cruisin

    Joined:
    Apr 1, 2014
    Location:
    Canada
    #7
    The sequential rate is not terribly useful as a benchmark, as not much is done sequentially.

    From: http://www.notebookcheck.net/ssd-versus-hdd-in-comparison.18750.0.html
    [​IMG]
    The blue bars are a 5400rpm Samsung, a 5400rpm Toshiba, a 7200rpm Toshiba, and a 7200rpm Seagate. These are the sequential rates. On this test 64MB/s is about 20-30% slower.

    [​IMG]
    This graph shows the strength of SSDs, namely that they still give good performance under random access. You can see that traditional hard drives are terrible at this.
     

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