A lot of attention has been paid to high-speed I/O interfaces for computing systems over the last five years. Flash-based storage media capable of multi-Gbps throughput have become very affordable. Display resolutions have also seen a rapid rate of increase. The necessity to support multiple such devices in both consumer and professional computing solutions have exposed the limitations of the traditional external I/O interfaces. While USB 3.x has become successful as an interface for high-speed peripherals, it does not handle display output. Intel has been attempting to solve this problem with Thunderbolt Technology since 2011. Unfortunately, the uptake outside the Apple ecosystem for the first two versions has been minimal at best. Thunderbolt 3, however, promises to be a game-changer. Systems and motherboards with Thunderbolt 3 support started shipping in late 2015. The first Thunderbolt 3 peripheral to appear in the market was the Akitio Thunder3 Duo Pro, a hardware RAID solution with two drive slots. This review looks at the various features of Thunderbolt 3 and what the Akitio Thunder3 Duo Pro brings to the table.

Introduction and Setup Impressions

Direct Attached Storage (DAS) units have been the go-to devices for consumers looking to store and have fast access to large amounts of data. The advent of high-speed interfaces such as USB 3.x and Thunderbolt have enabled a new generation of DAS units that allow the host system to access the member disks without any bottlenecks. We have looked at a few DAS solutions with Thunderbolt 2 before. Today, we are reviewing the first storage solution with Thunderbolt 3, the Akitio Thunder3 Duo Pro. The unit has daisy chaining support (i.e, two Thunderbolt 3 ports), a USB 3.1 Gen 1 device interface and a full-sized DisplayPort 1.2 output that is driven by the DisplayPort lanes in the Thunderbolt 3 link.

The Akitio Thunder3 Duo Pro is meant for desktop use and needs an external 90W power adapter (12V @ 7.5A). The chassis design also allows for stacking, if needed. In addition to the main unit and the power adapter / cord, the package also includes a Thunderbolt 3 cable (capable of 40Gbps data transfer) and a USB 3.1 Gen 1 Type-B male to Type-A cable. A cable-tie, quick setup guide, warranty terms and a reminder to update to the latest drivers / firmware for the host PC are also included. The detailed specifications of the unit are provided in the table below.

Akitio Thunder3 Duo Pro Specifications
Internal Storage Media 2x 2.5" / 3.5" Drives
Interface 2x Thunderbolt 3 + 1x USB 3.1 Gen 1
RAID Modes RAID 0 / RAID 1 / JBOD / SPAN - Hardware Selection Dial
Cooling Aluminium Chassis + Fan
Power Supply 100-240V AC Switching Adapter (12V @ 7.5A DC)
Dimensions 23.8cm x 14.3cm x 9.4cm
Product Page Akitio Thunder3 Duo Pro
Price $378

The gallery below takes us around the aluminum chassis. Important aspects to note include indicator LEDs for the two drives in the front panel and the perforations (which have a filter on the inside) that allow air to be pulled into the unit, over the drives and out through the fan. The rear panel is flanked on either side by screws that can be removed without the need for any tools. Loosening them allows for the external chassis to slide out.
The rear panel has a fan and a switch to control it (can be turned off for SSDs). Two Thunderbolt 3 ports, a full-sized DisplayPort 1.2 output, a power input jack and a USB 3.1 Gen 1 Type-B female port make up the lower part of the rear panel. A Kensington lock slot and the RAID-level selection indicator form the rest of the features.

The RAID-level selection indicator is covered by a plastic film from the inside that makes it impossible to accidentally change the RAID level without opening up the unit.  The gallery below shows the internal components of the Akitio Thunder3 Duo Pro.

On the board side of things, we have the Intel Alpine Ridge Thunderbolt 3 controller in its dual-port form (). The ASMedia ASM1153E fulfills the SATA to USB bridge functionality for the USB 3.1 Gen 1 device port. On the SATA backplane, we have the ASMedia ASM1062R SATA RAID controller that bridges 2x SATA III ports to two lanes of PCIe 2.0. The backplane also has an ASMedia ASM1456 signal switch to mux / demux SATA signals.

The setup process is simple, since the Thunder3 Duo Pro involves hardware RAID. Installing the SSDs or HDDs is a simple tool-less affair. Removal is a bit complicated, since the drives have to be gently tugged out from the SATA connector. A flat screwdriver can be used to set the desired RAID level (RAID0, RAID1, JBOD or SPAN). In case of a live switch of RAID level (i.e, change while the unit is powered on, it is necessary to press the 'Set RAID' button that is visible in the rear panel once the chassis has been slid off. Otherwise, one just needs to set the pointer to the desired RAID level and boot up the unit.

In the rest of the review, we first take a look at Thunderbolt 3 in detail, followed by a description of how our testbed was built and details of our evaluation methodology for the unit. We then talk about the various standard performance benchmarks. Following that, some special Thunderbolt-only aspects such as daisy chaining and its performance implications are discussed.

The Nuts and Bolts of Thunderbolt 3


View All Comments

  • danbob999 - Thursday, April 14, 2016 - link

    you are probably limited by your HDD speed, not USB3 Reply
  • DanNeely - Thursday, April 14, 2016 - link

    Depends how sequential the io is. Hdds are ~3x faster than usb2, so 4 hdds could bottleneck a 3.0 port. Reply
  • danbob999 - Thursday, April 14, 2016 - link

    They could in some rare case for short periods of time. In the real world, no one will even notice the speed reduction from USB 3.0. Speed will often be much lower, especially on writting, and even more if using RAID1. Reply
  • joos2000 - Friday, April 15, 2016 - link

    It's obviously not a raid 1 array though. Reply
  • theduckofdeath - Saturday, April 16, 2016 - link

    You're not trying to argue someone is using RAID 0 for data backup, are you? :D Reply
  • SpetsnazAntiVIP - Thursday, April 14, 2016 - link

    You would probably be better off building a NAS or SAN server using a hot swap server case or rack, a used $70 Xeon E5 2670, and connecting it to your PC with a 40 Gbps Infiniband link. Used 40 Gbps Infiniband PCIe cards are <$40 on eBay. Infiniband cables can be had for <$15. All of the server parts can be had used on eBay for cheap. You would have much more robust setup, much more configurable storage, better fault tolerance, be able to use more fault tolerant file systems like ZFS or CephFS, and the ability to upgrade and swap faulty parts, rather than replacing the whole storage solution. It would also probably be cheaper than an off the shelf 8 drive solution. Reply
  • SpetsnazAntiVIP - Thursday, April 14, 2016 - link

    Check out this writeup on an E5 2670 dual CPU build for an idea of how fast these processors are for $70 a pop used: http://www.techspot.com/review/1155-affordable-dua... Reply
  • zodiacfml - Friday, April 15, 2016 - link

    Yup. I was not impressed with the product and the technology. Type-C is a convenience thing though and not performance. A decent NAS can keep up with this. Reply
  • sor - Thursday, April 14, 2016 - link

    I really dislike the fact that we've got a single type of port with a dozen varieties of logos on either side, but I suppose it is better than a dozen ports. I wonder what we will do in the following generations as more protocols and protocol versions are added. Reply
  • Meteor2 - Friday, April 15, 2016 - link

    That's the whole point of TB3. It unifies the lot. Reply

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