External SSDs: Not super fast, but cheap, convenient and very small
As SSDs have taken over the storage world, there has been a quiet little change in external storage as well. Because they were intended to fit in place of laptop-size spinning platter drives, solid state drives were initially built to have the same format and cable connections as hard drives.
That's been changing and we're now all able to benefit. External drives are starting to crop up using the mSATA interface, a smaller, card-sized interface that's similar in form factor to the Mini PCI Express interface. In this review, we take one such tiny drive for a spin, er, access.
The drive I bought is the 256GB OTG (which stands for On The Go) from MyDigitalSSD. I picked mine up from Amazon for about $90. There are many similar drives available from other lesser-known vendors. If you're uncomfortable with the lesser-known brands that populate this category, you can get a Samsung drive for about $40 more.
My use case is relatively simple. I have a 2012 Mac mini (server version) with two 256GB SSDs installed. One of the SSDs runs OS X and the other runs Windows.
Because this is an active use machine, 256GB just isn't enough storage for the OS X side, so rather than yanking out a working install, I decided to add an external drive.
As you can see from the image below, it's tiny.
It doesn't require an external cable and connects to the computer via USB 3.0. Here's another view showing it on its side:
Configuration was simple. Open the box. Plug it in. OS X asked if I wanted to use the drive as a Time Machine drive. I declined. The drive then appeared in the Finder. Setup was done.
In terms of speed, it's certainly not the fastest solution, but it does blow the socks off the 7200 RPM hard drives I have installed internally on another Mac mini server. Given that those drives have never showed any lag and have handled just about anything I've thrown at them, performance well above them is certainly going to do the trick for most of the work this machine is expected to perform.
To test performance, I ran the Blackmagic Disk Speed Test. Here are the results:
For most applications, it's certainly fast enough.
The following table shows how performance stacks up for reading and writing compared to other Mac drives and configurations.
| Configuration | Write (MB/s) | Read (MB/s) |
|---|---|---|
| 2015 MacBook Pro internal flash storage | 1098.3 | 1049.8 |
| 2013 iMac with internal flash storage | 708.6 | 728.7 |
| 2012 Mac mini server with Apple internal SSD | 396.1 | 448.3 |
| >> 2012 Mac mini server with external SSD (this review) | 285.1 | 421.8 |
| 2012 Mac mini server with internal upgraded SSD | 174.2 | 501.9 |
| 2011 Mac mini server 7200 RPM hard drives | 79.4 | 89.1 |
Overall, it's a great little drive and very convenient. I'll probably pick up a few more over time as replacements for some of my thumb drives. The fact that it gets its power from USB and runs substantially faster than internal hard drives means this form factor will prove very useful in a variety of situations.
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