Submitted by andrewmriv on Wed, 05/21/2014 - 16:29

Back in December of 2013, near the time that I purchased my iMac 27” Late 2013, I was curious about getting some extra external storage. I wrote an article calledExternal Storage for my iMac which mentioned my uncertainty on which enclosure to get to serve my needs. I have finally made my decisions on what I ordered. I will discuss why I ordered them. Later on, I plan to write reviews on the products that I chose to let you know if I recommend them or not.

OWC Mercury Elite Pro Dual

This enclosure has two 7200RPM hard drives (HDDs) in it (3tb each in my configuration). The drives are in a RAID 0 configuration to have maximum capacity and performance.

The goal with this drive is to be used as a direct attached storage (DAS) to my iMac to serve as the main storage drive. My iMac has a small 256gb solid state drive (SSD) which will only be used to store system files and Applications. That means that all of the photos in my large iPhoto Library, all of the songs/videos in my large iTunes Library, all of Logic Pro files, and everything else will be on this drive. Thanks to the RAID 0 configuration, I plan on having a great performance.

While RAID 0 gives twice the performance and twice the capacity, it also gives twice the failure rate. If one of the two HDDs fails, then all of the data is lost.

OWC Mercury Elite Pro Qx2

My solution to that risk is the OWC Mercury Elite Pro Qx2. The goal of this is to have it plugged into my Airport Extreme Base Station as a Time Machine Backup. My iMac is in a different room from my Airport Extreme.

The idea here is to constantly have a backup of my OWC Mercury Elite Pro Dual saved on here in case one of the HDDs decides to fail on me. On top of that, in case there were to be a fire or something that happened in the room with my iMac, then this backup would likely be saved since it is in a different location.

The Airport Extreme Base station supports single external HDDs being plugged into its USB port. It is also even possible to plug in a USB hub to allow for plugging in more external HDDs. While that is nice, it is currently not possible to access the Disk Utility and create your own RAID array. So that means that the Airport Extreme does not support RAID.

There is a way around that besides for being a Network Attached Storage (NAS) that plugs into the router through an ethernet cable. With this enclosure, the RAID configuration is not setup on the Disk Utility. Rather, it is done in the enclosure. As a result, the Airport Extreme views this is a single large HDD.

USB 3.0? Why Not Thunderbolt?

So the iMac 27” Late 2013 that I have is equipped with two thunderbolt ports. Also, there are new thunderbolt versions of these products that I just purchased. Many people have wondered why I settled with using USB 3.0 enclosures rather than the Thunderbolt enclosures because of that.

The reason is because I would not see too much of a dramatic increase. Thunderbolt has the ability to severely outperform USB 3.0. In my research, I have found that since I am only using 7200RPM HDDs in my RAID configuration and no SSDs, I will not have a noticeable increase in performance. Therefore, it would be a waste of money to invest in the far more expensive thunderbolt enclosures.

Thank You

Now this article was a bit more of an announcement of the products that I purchased and what I plan to use them for since I am so excited. Later down the road, I will review the products and let you all know if I approve of them or not.


  1. OWC Mercury Elite Pro Dual
  2. OWC Mercury Elite Pro Qx2