OWC Mercury Elite Pro Qx2 Review

Other World Computing (OWC) USB 3.0, eSATA and FireWire 800, 4 Bay RAID Enclosure

(Updated: April 02, 2014)

Update Note:

This post was published in January without the accompanying charts and graphs.  Note there was a permissions problem with this site which manifested itself at the new year which was just enough friction to hold the posts for a few months.  The permissions problem has been solved and we should be off and running again.

Review Notes:

  • This article is a continuation of the “12TB RAID 0 Under $400” Study. We received our copy of the “OWC Mercury Elite Pro Qx2” and tested it using the same methodology as the 12TB USB 3.0 Hub RAID.
  • The equipment used in this review is the same equipment used in the 12TB USB 3.0 Hub RAID with the exception of removing the four Toshiba Canvio, 3 TB, USB 3.0, 5700rpm drives from their USB 3.0, bus powered enclosures and installing them in the “OWC Mercury Elite Pro Qx2”. This arrangement negates the use of a USB hub and reduces the cable count from 5 power cords and 5 USB cables to 1 power cord and one USB cable. This procedure ensures a fair comparison with the same drives, computer and software used in each test.
  • The drives were configured RAID 0 and were loaded with 2TB of data while in their 12TB USB 3.0 Hub RAID configuration. After removing the drives from their enclosures and installing them into the “OWC Mercury Elite Pro Qx2” we expected to demonstrate that the RAID 0 would come up normally with no Disk Utility configuration necessary, unfortunately, the “OWC Mercury Elite Pro Qx2” does not support 4 independent drives over USB. We would have to connect via Firewire or eSATA to test this and eSATA would require port multiplication. We did not test this functionality because we would have had to change computers, or add additional equipment and this is a rather obscure test of little value to most readers.
  • No separate drivers were required to support the “OWC Mercury Elite Pro Qx2”.
  • The “RAID Selector Dial” is the bear minimum. Although tiny, hard to read, and the dial positions are the opposite of the silk screened chart describing the positions (ie: the positions are from 4 at the top to 0 at the bottom while the instruction chart along side it is from 0 at the top to 4 at the bottom) the “RAID Selector Dial” and “Confirm” button worked well configuring the device between Independent, RAID 0 and RAID 5.


The “OWC Mercury Elite Pro Qx2” cannot be stored in a laptop bag, however, it does take up substantially less room than four USB 3.0 drives, a hub, 5 power cords with wall warts and 5 USB 3.0 cables. The “OWC Mercury Elite Pro Qx2” is easier to set up and operate with only one AC power cord, no wall wart and one USB 3.0 cable. You will not be using the “OWC Mercury Elite Pro Qx2” on an airplane, even with A/C power provided, unless you purchase the seat next to you.



The “OWC Mercury Elite Pro Qx2” shows marginal improvement over the 12TB USB 3.0 Hub RAID in average write speed, but the standard deviation of the results went from 2.3MBytes/sec to 24.8MBytes/sec. These results demonstrate a much less reliable and less predictable speed for the “OWC Mercury Elite Pro Qx2” against the same drives attached to a USB 3.0 hub configured by the Mac Disk Utility. Reconfiguring to RAID 5 gives us a 15% loss in average write speed, better than predicted, but the standard deviation of the results jumped to 44.8MBytes/sec.


The OWC Mercury Elite Pro Qx2 empty box is $279 and we paid $388 for the four 3TB drives for a total of $667. The OWC Mercury Elite Pro Qx2 RAID with 12TB of 7200rpm drives with twice the cache would cost $735.56 from B&H. This is currently the best price point for a large capacity (12TB), backup solution. The “OWC Mercury Elite Pro Qx2” comes with the USB 3.0 cable, the firewire cable and the SATA cable.


The “OWC Mercury Elite Pro Qx2” supports RAID 0, 1, 5 and 10 configurations.  The “OWC Mercury Elite Pro Qx2” supports eSATA, FireWire 800 and USB 3.0 Ports. The device is easy to set up and run for the “off-site” backup making it more likely you will run backups. In comparison it is unlikely you would set up and tear down individual drives hanging off a USB hub frequently. It is a nice looking device.


The “OWC Mercury Elite Pro Qx2” has a brushed aluminum enclosure. Although the “RAID Selector Dial” and “Confirm” button did not feel durable the rest of the device appears to be durable.  You will probably only use the “RAID Selector Dial” and “Confirm” button once and it resides behind the lockable front cover.


OWC Speed Test

Based on all the analysis presented in articles of this blog the only reason for going with more than two bays in a USB 3.0 array is for increased storage size. There is little speed gain between 2 and 3 drives when using one USB 3.0 port. There is no gain when using 4 drives off of a single USB 3.0 port. The conclusion that follows assumes a need for more than 8 TB for backup.

Purchase the “OWC Mercury Elite Pro Qx2” for your off-site backup. Use the 12TB USB 3.0 Hub RAID for your local backup (the storage that sits on your desk and does not move). This combination provides the most bang for your buck keeping in mind we will probably be replacing our entire backup strategy in a few years.

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