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OWC miniStack external hard drive: A speedy backup companion for your Mac mini

AppleWorld.Today | November 7, 2016 | By Steven Sande
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OWC miniStack

At least once a week or so, the team at Apple World Today publishes a reminder to keep your devices backed up. Apple has made backups as simple as possible with an iCloud-based backup scheme for iOS and Time Machine for macOS, but many people still leave their data vulnerable to possible loss. OWC is as dedicated as we are to making sure your data is backed up, and today we're looking at the new OWC miniStack 1TB USB 3.1 Gen 1 external hard drive.


The miniStack is designed to be your Mac mini's best buddy; it mimics the look of the Mac mini in every way, has the same dimensions, and is meant to be placed on top of or below your 2010 or later Mac mini. Of course, as an USB 3.1 Gen 1 external drive, it doesn't have to be used with a Mac mini...but it sure looks good when it's paired with the mini.

mac mini ministack

In terms of size, the miniStack is 1.4 inches thick and 7.7 inches on a side (36mm x 197mm x 197mm), and weighs 1.9 lbs (.85kg) without a drive.

The OWC miniStack can be configured as an empty storage enclosure into which you place your own 2.5- or 3.5-inch SATA hard drive, or in versions that include a 7200RPM 1TB ( $124.99 ), 2TB ( $142.99 ), 3TB ( $128.00 ), 4TB ( $199.99 ), 5TB ( $204.99 ) or 6TB ( $248.99 ) Toshiba hard drive. Our review drive was the 1TB model.

To keep the hard drive running cool, OWC wisely chose to place a fan in the enclosure. It's a special MagLev fan that runs at a very high speed for the best possible cooling, but makes very little noise. Compared to the two rather noisy drives that come with the Mac mini Server (late 2012), all you hear from the miniStack is a little bit of fan noise.

ministack ports

Power is provided by an included power supply with a thin cable that plugs into the back of the unit, and a USB Standard-A to Standard-B cable is included for connecting the drive to your Mac. There's a standard port for a Kensington locking cable as well; a nice touch that's not found on a lot of external drives.

While the miniStack works best with a Mac or PC with a USB 3.1 Gen 1 interface, it is backward-compatible with any Mac or PC that has a USB 2.0 interface.

A very complete and well-written Quick Start Guide is packaged with every miniStack. It's primarily meant to be used if you're installing your own drive, and includes full instructions on how to do so and then format the drive.

ministack bottom

OWC provides a 3 year warranty and 24/7 customer support, so in the exceedingly rare case that you might run into a problem with the miniStack, you're covered.


After connecting the power supply and cable to the miniStack, placing it atop the Mac mini, and pressing the power switch, a circular OWC HD icon appeared on the Mac desktop. With a double-click to open the drive, both Mac and PC versions of the OWC Drive Guide became visible, along with a PDF user guide, a ReadMe.txt file, and a folder marked OWC Software.

The ReadMe.txt file (which should probably be named "ReadMeFirst.txt" so that it's the first file that users open) notes that the OWC Drive Guide app should be launched. That app asks for permission to make changes on your Mac (requires admin login), then goes through a series of well-explained and clear screens to prepare the drive for use (see gallery below):

OWC Drive Guide

Once the final setup button is clicked, it takes about 2 - 3 minutes for the entire setup process to take place. At the end of that time, you can either take a look at the included software (Prosoft Data Backup 3.1 and Intech SpeedTools 3.91) or just begin to use the drive. The circular drive icon is replaced with a new icon that looks like the miniStack.

SpeedTools is a pretty handy set of tools; you can have the app do any number of drive-related tasks, such as scan a volume for bad sectors that it then logs, defragment files, test data transfer integrity, verify and repair volumes, run S.M.A.R.T. diagnostics (sadly, the Mac mini doesn't support that), analyze capacity usage, backup/restore a volume, get notifications when drive free space becomes low, examine preference lists (.plist files) for damage, and schedule all of the tasks to be run on a regular basis. Prosoft Data Backup is a well-done third-party backup utility.

However, most Mac users will probably choose to simply use the macOS built-in backup app Time Machine. Setting up Time Machine with the OWC miniStack takes just five clicks:

1. Click on System Preferences icon in the Dock
2. Click on Time Machine icon in System Preferences
3. Click on Select Backup Disk
4. Click on OWC HD icon
5. Click on Use Disk

That's easy! If you don't back up your Mac mini (or other Mac) now with Time Machine, this is about as easy as it gets.


One of the tools in the SpeedTools suite is QuickBench, which can be used to run a series of tests to determine just how fast an internal or external drive volume is. USB 3.1 Gen 1 (AKA "Enhanced SuperSpeed USB") can handle a maximum theoretical transfer rate of 5 Gigabits per second or 625 Megabytes per second. In reality, that rate is somewhat lower.

For small files (4KB to 1024KB in size), the average read rate was 149.911 MB/sec while the write rate was 149.024 MB/sec. For larger (2 - 10 MB) files, the average read rate was 202.832 MB/sec, write rate was 202.885 MB/sec. For the extended (20 - 100 MB) file test, the average read speed was 190.641 MB/sec, while the average write speed was 194.601 MB/sec.

How does this compare with other USB 3 external drives on the market? I ran the same tests on a Western Digital "My Passport" USB 3 drive and found that the miniStack was MUCH faster. For the WD drive, the small file read rate was 87.220 MB/sec and write speed was 82.082 MB/sec. The large file read speed was 99.753 MB/sec and write speed was 100.287 MB/sec, while the extended file speeds were 98.491 MB/sec (read) and 90.752 MB/sec (write).

Basically, for the large and extended file benchmarks, the OWC miniStack ran at about double the speed of the Western Digital My Passport external drive.


I was surprised by the speed of the OWC miniStack compared to a competing drive. The design is perfect for Mac mini owners who are looking for more storage or a way to back up their units, and the miniStack runs quietly and efficiently. Add to that the excellent warranty and customer support, and you've got a winner.

Apple World Today Rating (Out Of 5 Stars)