Neil Turner's Blog

Blogging about technology and randomness since 2002

The technical superiority of Dropbox

Although I’ve made a few edits to my SkyDrive vs Dropbox vs Google Drive blog post from last week, I haven’t gone into much detail about some of the more technical aspects of the services. Dropbox, being the more mature of the three, has some clever tricks up its sleeves which Google Drive doesn’t have, and SkyDrive also appears to lack too.

LAN sync

LAN sync is a DropBox feature that will share files between computers on the same network. If you have Dropbox open and signed in to the same account on two computers on the same network, and save a file into your Dropbox folder on one computer, then as well as uploading that file to Dropbox’s servers, that computer will also send the file to your other computer over the network. This is much quicker than the other computer waiting for the file to be uploaded to Dropbox’s servers to download it again, and saves on your bandwidth. Google Drive doesn’t have LAN sync, and I don’t think SkyDrive does either.

Sadly, LAN sync only works between desktop computers; if you save a file on your iPhone, it won’t appear on your desktop until your desktop has downloaded it from Dropbox’s servers, even if you have Wifi enabled on your iPhone.

Delta syncing

If you edit a file that’s already in your Dropbox, Dropbox will detect which bits of the files have changed, and then only upload those changes. Google Drive isn’t quite so intelligent and will just upload the whole file again. So if you have a 750 MB high definition video in your Dropbox, and change some of the metadata in the file’s header, Dropbox may only need to upload a few kilobytes (and other computers on your Dropbox account will only need to download those few kilobytes too). Google Drive will instead upload the whole 750 MB file again. Coupled with the lack of LAN sync, as mentioned above, that’s a lot of bandwidth being used unnecessarily.

Duplicate file detection

If you put two identical copies of a file in your Dropbox folder, Dropbox will detect that they’re the same and just upload one copy, but make sure that both copies are on its servers (note that both copies will count towards your total storage space). Google Drive will still upload both files regardless of the fact that they contain the exact same data.

Resurrecting deleted files

Dropbox keeps a file history going back 30 days, meaning you can recover deleted files and also revert to older versions of existing files. Google Drive doesn’t appear to let you revert file versions but deleted items go in a trash folder. But Dropbox is also clever about deleted files. Say you have a file in your Dropbox folder, which you then drag to the Recycle Bin; Dropbox will delete the file, but let you recover it on the web if you wish; but also, if you undelete that file on your desktop and put it back into your Dropbox, Dropbox will detect that the file was already on its servers and just make the file live again – it won’t need to upload it again.

Memory efficient desktop client

Performance of cloud storage desktop clients on Mac OS X Lion
Client name32/64-bitIdle CPU UsageReal memory usageVirtual memory usage
Dropbox32-bit0 %41.7 MB56.6 MB
Google Drive32-bit1.5 %61.7 MB64.6 MB
SkyDrive64-bit0.3 %17.1 MB22.5 MB

I ran all three clients at the same time and compared their performance using Mac OS X’s Activity Monitor. SkyDrive is arguably the clear winner here – although it uses a little more CPU than Dropbox, its memory usage is tiny, and it’s the only one of the three to take advantage of OS X’s code operations for 64-bit applications. Google Drive is a hog by comparison, using almost 3 times more memory than SkyDrive and much more CPU – and this is whilst idle, i.e. not syncing files. Furthermore, this is despite not having the advanced features that Dropbox has.

Obviously Google Drive is new and it’s likely that future releases will reach closer feature parity with Dropbox, but right now, Dropbox is technically superior than Google Drive, thus working faster and saving your bandwidth. I haven’t looked into SkyDrive as much as I possibly should have and will revisit this post when I have more information.

Much of the information for this article is sourced from this post on Dropbox’s foums.


  1. How did you get SkyDrive to use such low numbers? I have all three on my MacBook Pro and my results show similar for mostly the same for Dropbox (5GB) and Google Drive (0.07GB) but SkyDrive (45GB) is pushing 285MB Real & Virtual memory and bouncing from 10% to 100% CPU usage, mostly handing up in the 100’s. Could be the file size differences, but if that’s the case, what’s the point in using SkyDrive if the more you store the more CPU and memory it uses? I will test SkyDrive on my Windows box and see if its the same or just a Mac issue.

  2. yo sam, how many files do you have on skydrive? like dropbox and google drive, the more files you have the bigger the client gets (probably because it has to have some kind of database of all the files and changes in memory, so it can record and sync everything in real time), still i do agree with neil, seems like skydrive client is a bit more slim both in win7 and mac lion, but just as a sidenote, google drive and dropbox have no file number limit, but skydrive has a 150.000 files limit! yeah most people dont know… whats the point of skydrive cheap storage if you can only save 150.000 files…

  3. I am syncing about 1.5GB using Google Drive. I think my usage is atypical because it’s made up of a very large number of small files. Google Drive uses 550MB of RAM even when idle, and uses one entire core of my CPU when syncing in any way. Also; files sync incredibly slowly.

    I was able to ignore the problem on my home PC which has oodles of RAM but on my laptop this application is a disaster compared to Dropbox which appears to manage memory, files and file lists much more intelligently as you point out.

  4. Just curious how you verified that Dropbox was only uploading deltas. Also wondering if you verified whether this is actually the case, or is it an assumption: “(and other computers on your Dropbox account will only need to download those few kilobytes too)” ? I agree with your rationale – just wondering if these are just Dropbox claims or if you tested it somehow?

    • It’s something of an assumption, mostly based on the time taken for various file operations to complete: Dropbox completes uploads much more quickly. I am also using observations from the quoted thread on Dropbox’s forums.