I am stuck in a situation where I need more storage on my macbook. Most of the space is used up by dropbox which is used for work and although I have tried selective sync it is getting a bit annoying.

I could get an external usb drive and put my dropbox on it but having the extra hard drive would make me less mobile as I sometimes like to walk with my laptop or move from room to room.

A solution I am now considering is a 128gb SDXC card which would fit nicely in my macbooks SD slot and have enough room for my entire dropbox.

Is an SDXC card a good alternative to an external hard drive?

Can I expect it to work just as quickly?

Will it be as stable and as reliable as a USB hard drive?

  • IO speed is much slower than a HDD
    – Jeremy
    Oct 13, 2015 at 9:39
  • Why not just replace the internal HDD with a larger one? Oct 13, 2015 at 14:58
  • @Ƭᴇcʜιᴇ007 New Macbook pros have their HDD soldered to the motherboard, hard to replace. Most stores will only replace your macbook pro with a better one (they won't change the HDD) which is a cost of maybe 8x that of an SD card.
    – Matkey
    Oct 13, 2015 at 15:12
  • I want to add that this works really well, I only keep the dropbox on the SD card and have not noticed any worse performance vs the HDD, I would say the difference is too small to notice with regular documents and excel files. I did however break the sd card just recently, it came apart from the wear of it sticking out of my macbook. No damage to the macbook itself and I was able to just buy a new sd card and sync my dropbox again. Not the best solution but it does work pretty well and its cheaper than replacing the hard drive or computer.
    – Matkey
    Nov 14, 2016 at 14:56

3 Answers 3


I would view this as a short term solution for a number of reasons:

a) Internally, the SDXC reader in your laptop connects via USB, and SDXC cards are rarely as fast as internal SSD storage. So it will be slower that your internal storage, and a little slower than many external USB 3 hard drives. Chances are it will be fast enough to keep you happy though!

b) Leaving the SDXC card in the laptop#s slot all the time will leave a card poking out of the slot a little. Every time you bump the card you wear out the card and the slot a little bit.

c) SDXC cards are not designed to be written over and over and over again like a hard drive. They are by no means fragile these days but I would always expect the hard drive to last longer, even if the warranty on the two storage devices was identical.

d) A 128GB SDXC card is not cheap.. if you check out the used Mac market you may find it is cheaper to sell your current beast get a beefed up machine? Maybe! Could you tell me which machine you have?

e) It sounds like you should be managing your file sizes better. How long before you start shopping for a 256GB SDXC card? :(

  • You make some very good points. c) I feel fairly safe as the files are almost always synced via Dropbox but something to keep in mind when shopping. d) A 128GB SDXC costs about $50 in my area which is not a lot more than an external hard drive. e) The Dropbox is work related which is why it is the size it is and I do not expect it to increase too much in size over time. Thanks!
    – Matkey
    Oct 13, 2015 at 10:40
  • Also, Nifty sells micro-SD card adapters that sit flush with the side of the computer. This way you can avoid point #2. Oct 15, 2015 at 16:19
  • @DSchlachter Oh nice
    – Matkey
    Oct 28, 2015 at 17:02

Don't rely on SD cards!

But as you rely on Dropbox - go with it! (If you use it only for Dropbox.)

Unless you do something that results in many hundreds or thousands of daily updates in your dropbox, I guess it's worth the risk. I think a harddisk or SSD is much more reliable, but as everything is backed up, the risk is minimal.

And what about a small USB3 stick?

  • A USB3 stick costs about the same but still has the effect of me being less mobile. The stick has more of a chance of breaking off if I bump into something compared to an SD card. If I want to put my macbook in a bag I would need to take the USB stick out but an SD card can be kept in.
    – Matkey
    Oct 13, 2015 at 15:15
  • I don't know if you downvoted me, but as I say: go with it! Just don't rely on it. If you sync with dropbox, you have a good backup, and that's what counts. If things break, bad luck. If not, live happily.
    – SPRBRN
    Oct 13, 2015 at 15:34
  • I am unable to downvote you as I only have 11 reputation (15 needed).
    – Matkey
    Oct 13, 2015 at 15:38

Apple told me NOT to put my Photos library on an SD card as it is constantly being updated. I am somewhat on the side of memory is memory, but I'll also agree that SD cards are normally used with very limited numbers of read and write operations.

FYI, there is a special adapter for a microSD card that doesn't stick out of a computer's SD card slot (only enough to be able to remove it)

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