SD slot bus/speed for iMac mid-2011 (PCIe or USB)?

Discussion in 'iMac' started by bestcea, Aug 15, 2011.

  1. bestcea macrumors newbie

    Joined:
    Aug 15, 2011
    #1
    Apple article http://support.apple.com/kb/ht3553#4 is not specific as to what speed, and Apple tech support discredited the article, so reign of confusion.

    Article Q&A says: "What is the maximum speed that my computer can use when reading and writing to an SD card in the SD card slot?
    Macs that use the USB bus to communicate with the SD card slot have a maximum speed of up to 480 Mbit/s. Newer Macs use the PCIe bus to communicate with the SD card slot and can transfer data at a much faster rate."

    Presumably, the mid-2011 iMac would be the "newer" mac, but when I asked Apple tech support to tell me the data rate he said it was wrong to infer the mid-2011 had the SD slot on a PCIe, but rather, it has it on a USB bus. I suppose Apple tech support is right and the article is wrong or referring to a future imac.

    Anyone have any additional info on this?
     
  2. The-Pro macrumors 65816

    Joined:
    Dec 2, 2010
    Location:
    Germany
    #2
    You can look in your system information.
    I only have one machine with an SD card slot, thats my 2010 MBP. Under USB in the system information, it says Internal Memory Card Reader. So I presume the SD reader is USB powered. Have a look in your system information. I guess that if it doesn't say Internal Memory Card Reader under USB for you then its not USB powered. It would show up somewhere else under system information then.
     
  3. g-7 macrumors 6502

    g-7

    Joined:
    Feb 14, 2006
    Location:
    Poland
    #3
    On my mid-2011 iMac (21.5") the card reader uses the internal USB bus.
     
  4. The-Pro macrumors 65816

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    Dec 2, 2010
    Location:
    Germany
  5. willsoriano, Mar 11, 2012
    Last edited: Mar 11, 2012

    willsoriano macrumors member

    Joined:
    Mar 21, 2011
    #5
    I am only replying to this because I noticed that on my mid-2011 27" i7 its listed under USB and SD card reader. Then Comparing to my late-2011 MBP i7 Card Reader has an actual speed and not listed under USB, which would explain why my external HD is slow for transfer because of all the USB ports being on the iMac sharing the same data flow. See attached pictures.

    [​IMG]
    [​IMG]

    oddly they also have different versions of lion running... Its a conspiracy!!!!
     
  6. Bear macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #6
    Interesting about the MacBoook SD reader.

    As for Disk Speeds and USB. The iMac has 2 USB controllers. you need to make sure your devices are spread across the 2. System Information will help you sort that out.

    Also, FW800 is almost twice as fast for disks as compared to USB 2.0.
     
  7. willsoriano macrumors member

    Joined:
    Mar 21, 2011
    #7
    Yeah the problem is I bought all of my Mac stuff withen a moth or so after. The external hard drive I want to use is USB. And im not about to spend more money.

    Oh well
     

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