SD Card (JetdriveLite/Storedge) and Power

Discussion in 'MacBook Air' started by MikePembo951, May 24, 2014.

  1. MikePembo951 macrumors member

    May 25, 2013
    I have a MBA 2013 13" 8GB 128GB. I was thinking of increasing the space with a Transcend Jetdrive Lite 130 (128GB) or a PNY Storedge (128GB) and have a few questions:
    1) By how much do these SD cards decrease battery life? (I've heard it stops them sleeping). My MBA is on for at about 9-12 hours each day (it's my primary machine), and is left charging overnight.

    2) How well does it cope when mounting the SD card after being put to sleep or when the lid is closed? Is it instantaneous? Would it affect programs such as iTune s if I had my iTunes library on the SD card and left iTunes open whilst sleeping?

    3) What are the realistic speeds of the cards? Would it be possible to keep large programs on them (such as logic and Xcode) and still run them well?

  2. Dweez macrumors 65816


    Jun 13, 2011
    Down by the river
    I have the 128 gig PNY card in my 2013 13" MBA and it's very seldom removed from the SD slot. The device is always there when I open the lid and bring the machine out of sleep.

    I"m sure it has an impact on battery life, but have no data regarding that issue. My MBA goes to sleep just fine with the PNY card installed.

    Performance - I get around 60 MB/s write and 90 MB/s read out of mine using an ExFAT filesystem. Slow compared to internal storage, but not an issue as mine is used for media and documentation.

    Check this thread for more real world experiences.
  3. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Give this a read. Your MBA supports "standby mode" and goes into that mode after three hours sleep. If you have that SD card plugged in, it will still sleep but will not enter standby which gives far longer battery life when sleeping.

    You are normally looking at around 1% battery drop per hour of normal sleep vs. up to thirty days of battery sleep in standby mode.
  4. iizmoo macrumors 6502

    Jan 8, 2014
    I just got the PNY StorEdge last week, the operation isn't a problem, machine seem to be sleeping just fine. My card is set with a GUID partition table and encrypted (just safety in case of theft).

    From using it so far, it does not seem to be impacting battery life significantly to the point where I'm really noticing it. But then again, I'm using it as storage for many work project files that I do not access all that often, or for games, which again is not constant read access. Constantly writing several hundred thousand small files to the card over several hours did showed some battery drain. How much battery get use I think will depend a lot on your specific usage profile.

    I use mine with a lot of small files, so the read and write is not as high as Dweez. I'm getting 8MB write, 77MB read in Blackmagic, but my file system is OSX Journaled (HFS) and encrypted. ExFAT write speed might be different, but I can sacrifice some speed for security.

    I would not put XCode on it because I use XCode too much and it's very modular, so waiting for the modules to load as you do things would get really annoying.
  5. Islanti macrumors newbie

    Feb 17, 2009
    I have the 128GB TheMiniDrive for my 15" late 2013 rMBP. I have had a few issues with the device. I'm not sure if the Mac will go into Standby (AKA hibernate) as I haven't tested that. I have noticed that sometimes coming out of sleep the card isn't re-mounted. Re-inserting it fixes the issue, but is a pain. Usually I just reboot, which is faster and fixes the issue.
  6. iizmoo macrumors 6502

    Jan 8, 2014
    Umm, or you can install sleepwatcher and have it unmount and remount the SD card as your mac goes into and out of sleep. Also fixes the problem of deep sleep I believe...

    Make sure to stop any services or app using anything on the SD card though.
  7. scaredpoet macrumors 604


    Apr 6, 2007
    While I haven't timed the actual difference in battery life with SD mounted vs no card, I can say that the battery life estimate my 2013 MBA reports is cut down by half when a card is inserted, as opposed to no card. And the actual battery life does noticeably go down quicker.

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