External Hard Drive Docking Station Reviews: What is the best dual hard drive dock?
In this age of digital data proliferation, digital storage is almost always in short supply. To accommodate this thirst for digital storage space, many of us resort to buying multiple external hard disk drives (HDDs) each with its own USB or similar connection hardware, and each with its own power adapter. In addition, as we upgrade computers over the years, many of us are left with a trail of old laptop and desktop computers that are too slow to deal with today's fast moving digital pace but still have usable hard drives inside, if only they were more accessible. To address these problems, electronics manufacturers have come up with the hard drive docking station that effectively turns all your spare hard drives and solid state drives (SSDs) into hot-swappable storage units not unlike the old magnetic tape cassettes of yesteryear. Hard drive docking stations come in several flavours from those that handle a single HDD or SSD to other more professional HDD docks that can handle an array of drives. Since here at DeskTopVibes.com we are focused on consumer computing hardware, we favour the 2-bay or dual hard drive docking station for its balance between technical flexibility and yet still reasonable price. To find the best dual HDD docking station, one needs to know first what technical specifications to look for before then choosing a reputable manufacturer.
What to look for in a Dual Hard Drive Dock
2.5" and 3.5" drives
First and foremost, the HDD dock should be able to handle the two most common sizes of hard drive / SSD, namely the 2.5" laptop-format drives and the desktop-sized 3.5" drives. Fortunately, the majority of dual hard drive docking stations on the market today are able to accommodate both standard formats, so ensuring this feature is included in your future HDD dock should not be too difficult.
The SATA standard
Most consumer hard disk drives and SSDs connect via a SATA connection, although other variants of SATA, such as mSATA and M.2, are also becoming more popular especially in ultra-thin laptops. The SATA protocol has evolved over the years with each iteration doubling the theoretical maximum speed at which data can be transferred. The oldest of these, SATA I, has a theoretical maximum data transfer speed of 1.5 Gbps. This was followed by SATA II with a maximum data speed of 3 Gbps, and then more recently, by SATA III which has a maximum speed of 6 Gbps. Fortunately, the SATA standard has been developed to be backwards-compatible and forwards-compatible, meaning older SATA drives will work when they are plugged into newer SATA interfaces, and conversely, newer SATA drives will work in older SATA hardware, albeit always at the maximum data transfer rate of the lower SATA standard. What this means for SATA HDD docking stations is that they will accept and run older SATA drives from obsolete computers, while at the same time being compatible with current SATA HDDs and SSDs, and should remain capable of running future versions of SATA-based storage drives as well.
Hard drive docks are essentially adapters that facilitate the transfer of data from one hard drive to another, so the basic question users need to ask is how fast can these HDD docks transfer data. Data transfer is usually measured in gigabits per second (Gbps), which can be translated into the more commonly used data parameters of gigabytes (GB) and megabytes (MB) by dividing the Gbps by 8 to get the number of GB/s, and then multiplying by 1000 to get the more familiar metric of MB/s of data.
8 Gbps = 1 GB / sec = 1000 MB / sec
USB vs eSATA
The HDD dock connects to a computer via its external interface. Today's current defacto standard for the external interface is a USB 3.0 connection, which has a theoretical maximum data transfer speed of 5 Gbps. USB 3.0 is backwards compatible with the USB 2.0 (480 Mbps) and should also be compatible with USB 1.1 (12 Mbps) standards (although this may not be the case for some less reputable electronics manufacturers) which means that USB 3.0 HDD docking stations will also work via legacy USB ports, although at the much lower data transfer speeds of the older USB standards. A more recent USB standard, USB 3.1, with its maximum speed of 10 Gbps, has also started to make an appearance on some HDD docking stations on the market. However, currently, it seems pointless opting for an HDD dock sporting a USB 3.1 port as the maximum speed data can be transferred in an HDD dock will anyway be limited by the maximum speed of the internal hard drive SATA connections, i.e. 6 Gbps in the case of SATA III.
Another common external interface found on HDD docks is the eSATA port, which can be assumed to be equivalent to the internal SATA connections, but designed as an external interface. However, eSATA ports are not all that common on computing hardware so, in general, the slightly slower USB 3.0 port is currently the preferred external interface when it comes to hard drive docking stations. In reality, data transfer speeds rarely, if ever, reach their theoretical maximums due to mechanical limitations of the hard drives themselves, therefore using eSATA at a maximum speed of 6 Gbps versus USB 3.0 at maximum speed of 5 Gbps will not really make any difference to the actual data transfer speeds one observes in real life.
The USB Attached SCSI Protocol or UASP is a protocol that enhances the effective data transfer speed over the USB interface. However, this is not to say that the USB 3.0 interface can go even faster than its theoretical maximum of 5 Gbps, but rather that with UASP support, the actual real-life data transfer speeds that one sees over the USB interface comes closer to its theoretical maximum. UASP also has the advantage of using less CPU resources when transferring data over the USB interface. For UASP to do its job, one not only needs a dock that supports UASP but also a computer and operating system that has inherent support for UASP. This means modern computers running Microsoft Windows 8 and upwards, Mac OS X 10.8 (Mountain Lion) and above, or more recent versions of Linux starting from version 3.15 can all take advantage of the improved performance attained with UASP when connected to a HDD dock which also supports UASP.
Hard drive duplicator dock
Offline hard drive cloning is a feature found on some dual HDD docking stations, which permits the cloning or identical copying of one drive on to another blank drive without the need for a computer. It is by no means a required feature and one needs to think carefully whether it is really useful in their own specific circumstances, as how often does the typical consumer need to make an exact copy of a hard drive? In addition, on the odd occasion when one does need to make a copy, this can usually be achieved via the computer instead. Some might argue this feature can be used as part of your back-up strategy, making copies of drives that will be taken off-site. However, software-based backup solutions, like Time Machine on Mac OSX, do a much better job by only copying files that have changed since the last backup as opposed to rewriting over the whole drive each time. So in our humble opinion, unless your job or similar requires lots of hard drive and SSD cloning, this feature remains merely a bonus feature.
Popular Dual Hard Drive Docking Stations
^ max speed limited by the internal SATA III standard of 6 Gbps
Best external hard drive docking stations
Inateck usb 3.0 hard drives docking stations
Inateck dual HDD docks come in a few different formats, the most popular of which are the Inateck FD2002 and the Inateck FD2005 which are actually the same hardware under the hood but in two different case designs. Both models use the same ASM1156 chip set, and use a USB 3.0 interface with UASP support to connect to a computer, giving them a theoretical maximum data transfer speed of 5 Gbps (or 625 MB / sec). The FD2002 has a more traditional case, while the FD2005 has been designed with more radical features and lines which one more often finds on gaming computer hardware. Inateck has also more recently come out with an updated model, the FD2002C, which is essentially the FD2002 but with a USB 3.1 port instead of a USB 3.0 port. In addition, the USB 3.1 port uses the latest reversible USB-C type socket as opposed to the more common USB-B type socket but which will future-proof it for connecting to the latest computing hardware. However, the presence of the USB 3.1 standard adds little to the data transfer speed of the HDD dock due to the speed limitations SATA III.
Inateck is a international company with headquarters in both the United States and Germany, with a reputation for selling high quality electronics accessories but at very reasonable prices.
StarTech hard drives docking stations
StarTech has tried to cater to the whole market in dual HDD docks by fielding an assortment of models each with slightly differing characteristics. For example, the StarTech SDOCK2U33, SDOCK2U33EB, and SDOCK2U313 HDD docks are essentially all the same hardware but with different external interfaces. The SDOCK2U33 model has a USB 3.0 port, giving it a maximum theoretical data transfer speed of 5 Gbps. The SDOCK2U33EB has a USB 3.0 port and an additional eSATA port, enhancing its maximum theoretical data transfer speed to 6 Gbps, the maximum of the eSATA standard. The SDOCK2U313 dock, on the other hand, has a USB 3.1 port, however, although the theoretical maximum data transfer speed of the USB 3.1 standard is 10 Gbps, the internal SATA connections to the hard drives limit the maximum data speed to the theoretical maximum of the SATA III standard, namely 6 Gbps.
StarTech is a Canadian company that sells electronics hardware internationally. It has an excellent reputation for making and selling high quality electronics accessories, however, with the higher quality comes higher prices, which is indeed the case with StarTech-branded dual HDD docking stations.