A review of the CalDigit Tuff, plus an APFS benchmark

As a follow-up to our preview, today we take a look at the CalDigit Tuff external harddrive.

Chuck the CalDigit Tuff your backpack

CalDigit Tuff unboxing 2Everything about the Tuff tells you that it’s aimed for the mobile crowd. This thing is meant to be resistant to throwing around. Next on their list seem to be storage space, 2 TB is pretty respectable at the moment. If you’re looking for performance, you’re better off picking one of our recommended external SSDs of course.

However, for an external harddrive, CalDigit does seem to want to bring the performance to your attention: the transfer speed is mentioned in the shortlist specs on Amazon: max. 130 MB/s. Read on to see if they deliver.

As for portability, the weight is specced at 0.6 lbs/270 gram. As you’d expect from a ruggedized harddrive, it’s a pretty hefty device.


Our tests are done on a base model Late 2016 15″ MacBook Pro with AmorphousDiskMark, a disk benchmark that mimics the interface of the well-known Windows software CrystalDiskMark.

It seems CalDigit underpromises and overdelivers; the sequential file transfers are actually higher than the specified 130 MB/s.

We also hooked up the CalDigit Tuff to a Windows laptop to read out the internal drive characteristics. Note that since CalDigit doesn’t actually specify these, they could change if they switch this component. But for completeness’ sake, here it is:

CalDigit Tuff crystaldiskinfo

What we think is interesting here, is that the CalDigit Tuff is a 5400 RPM drive. And not, as 9to5Mac notes in their otherwise nice review, a 7200 RPM drive. Furthermore, we see a Seagate drive with a nice 32 MB cache.

Bonus topic: file systems

CalDigit Tuff formatted as APFSIf you’re an iPhone user, go ahead and see which version of iOS you’re currently running. Chances are, it’s running 10.3 or higher and that means the file system of your phone is not plain old HFS+ but the new Apple Filesystem APFS.

As for macOS, the file system is not officially released but it’s in beta and comes with macOS Sierra. If you’re not scared of the terminal, then you can format an external drive with this new file system. About four commands are necessary, see screenshot.

Last month, the MacObserver found that performance of APFS on macOS is lagging behind HFS+, so the following benchmark results are neither worrying nor unexpected. What’s interesting is that although the performance of copying large files is much lower, shorter reads and writes are actually faster:

CalDigit Tuff Benchmark formatted as APFS

So if you’re not afraid of currently experimental file systems, and you use an external harddrive as scratch space for smaller files, perhaps you want to format it as APFS.

Note: should you want to revert to HFS+, simply type:

$ diskutil apfs deleteContainer /dev/diskXsY

where X and Y are obviously the disk number and partition number as shown by the command:

$ diskutil list

Our verdict

If you need the lightest and fastest storage space, get an SSD from our recommendations.  If you value shock resistance and storage space, then the CalDigit Tuff is an excellent drive and as a consequence, we’ve added it to our recommended harddrives.

The device we tested was provided for free by CalDigit.