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Thread: Memory chip speed faster than required in user manual

  1. #1
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    Memory chip speed faster than required in user manual

    User says class 6 or better, class 10 ranges from 20meg per second to 95 (emerging tech top of the line) yesterday there was a 64 gig that operated at 30 meg per sec

    Is there any value or benefit to these hyperspeeds? Can the camera push that much data?
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  2. #2
    Super Moderator Kayaker72's Avatar
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    A few of us tested this awhile ago. The short answer was that the camera itself becomes the limiting factor after a certain point (~50 MB/sec for the 7D and ~60 MB/sec for the 1DIV). So faster cards will not help in camera, but should help when transfering to your computer if using a good CF card reader/etc.

    Here is a link:
    http://community.the-digital-picture...?t=5294&page=8

  3. #3
    Senior Member neuroanatomist's Avatar
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    Seems I never posted my tabulated results in that linked thread, or at least, I can't find the table. But I'd slightly disagree that the camera is limiting after ~50 Mb/s for the 7D. True, the difference going from a 60 Mb/s card to a 90 Mb/s card is not huge, but it's there - a few extra frames in a long, continuous burst and a second or so faster recovery after a burst. I'll post my results here, they pretty much agree with Brant's in the other thread (and you can see the need for updated firmware, too). Even on a relatively slow camera like the 5DII (3.9 fps) the 90 MB/s card makes a difference over the 60 Mb/s card.


  4. #4
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    The testing everyone did in the thread Brant linked was primarily looking at the difference between the 60mbs and 90mbs card. For the questions Busted Knuckles posted the answer is yes the card is going to matter (somewhat). The 20mbs and 30mbs cards will limit his performance.

    As Brant said, in camera the 7D and 1D IV maxed out at about 50-60 MB/sec, and the only way you really notice this is the cameras ability to recover from a full burst. If you continue to shoot with the button held down after a burst, over time you will get a few less frames because of the slower recovery speed. The difference for the most part is inconsequential for the 5D II and the 7D, and at best very fractional with the 1D IV.

    As Brant said, you get a faster transfer speed.

    If you want to do video, get the fastest card you can.

  5. #5
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    I have a lowly T3i, and video is the question.

    I have a flock of 20mb/sec class 10 that work "ok" I notice that I have to reformat them every so often to clean up the FAT so the write speeds are at max.

    It seems SD cards get fragmented quickly.
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  6. #6
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    Thanks for the info - seem this topic is well studied.

    It sounds like the manufacturers are anticipating 4k video to be put onto a chip.

    What a wonderful world of technology we live in. I can remember when a 10 meg hard drive was a couple of hundred bucks!!! ooof looking forward to the future.
    If you see me with a wrench, call 911

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