Technology content trusted in North America and globally since 1999
8,585 Reviews & Articles | 67,035 News Posts

OWC Mercury Helios 3 Thunderbolt 3 Enclosure Review

OWC Mercury Helios 3 Thunderbolt 3 Enclosure Review

We pair the OWC Helios 3 Thunderbolt 3 storage enclosure with the Intel DC P3700 SSD. Join us as we check out the performance.

By Tyler Bernath | Dec 13, 2017 10:50 am CST
Rating: 94%Manufacturer: OWC

Thunderbolt is the apex of external connectivity I/O. With Gen 3, we now have access to 40 Gb/s of throughput which opens up the window to a whole host of devices. OWC, over the last two generations, has deployed the Mercury Helios to enable users a greater level of customization with Thunderbolt technology.

The Mercury Helios 3 is a Thunderbolt 3 enclosure as the name suggests. It is a single slot solution supporting half-length cards up to 7.5", full height and double width as well. Features include dual Thunderbolt 3 ports allowing daisy chaining up to five additional devices along with miniDP for displays supporting resolutions up to 4K60. Internally, we have a full PCI-E x16 slot with 75 watts of power support.

Compatibility includes macOS 10.12 and later, Windows 10, and BootCamp support for Windows. The MSRP comes in at $199.99 with a three-year warranty.


With packaging, OWC has followed previous Helios solutions with their designer blue and white box. A large image of the enclosure is placed on the front with a few marketing details at the bottom left.


The spine houses a full specifications list including the footprint of the enclosure.


Included with the Helios 3, we have the power adapter and Thunderbolt 3 cable.


The power adapter is rated at 12v 7.5A which gives roughly 90 watts of power.


The front of the unit features a mesh that allows air to pass through and is pushed by the included fan. We have subtle branding here on the front.


The backside gives us two I/O plates and down below the power input, miniDP and dual Thunderbolt 3.


For testing, we have in the lab an Intel DC P3700 SSD. To the right, we get a glimpse of the air intake fan.


Apart from using the Helios 3 with PCIe SSDs, we installed a few of our NICs in the enclosure to see how they do with clearance. As you can see, our PCE-AC88 does have issues in the antenna area making it quite difficult to install the antenna leads.


Our 10Gbe NIC too has issues with cabling, but only when trying to remove them, the bottom latch of the cable is difficult to reach.


To start our performance testing, we installed the DC P3700 in the enclosure. Since we are using a Windows machine, I did Install the Intel NVME driver. With that said, I was able to reach a score of 13,629 in Anvils.


With ATTO, we see write performance hit peak performance around 128K at 1,844 MB/s while read performance didn't reach a peak until 1M at 2,804 MB/s.


CDM we threw in there for comparison as it showed more of the same. 2796 MB/s read and 1866 MB/s write at QD32.

With the limited number of Thunderbolt enclosures I have had come through, I can honestly say I'd put the Helios 3 right up there with the Akitio unit tested a few weeks back. The full aluminum design seems to be thick enough to support a drop or two and the structure of the unit supports whatever card you need to install. I didn't have any issues with sharp corners or unfinished port edges with this unit.

The performance was top notch supporting full 40 Gb/s throughput, and as you can see, we lost no performance with our P3700 SSD. At the peak, we reached 2800 MB/s read and 1850 MB/s write, which is on par with the result when the card is installed internally. Using our Wireless NIC, we did find slight issues with the proximity of the SMA connectors and the enclosure but no performance issues to speak of. Last, I used our 10Gbe NIC from ASUS in this unit with solid success but again the locking pins on the cables do have an interference issue with the enclosure.

With all of that said, OWC has put together a simple but very solid solution for those wanting to customize the devices they hook up to their Windows or macOS-powered machines. This solution offers additional Thunderbolt 3 and miniDP which put it above competing solutions in my book and adding to this they have priced the Helios 3 aggressively allowing it to come in a full $50 cheaper than the Akitio Node.

Tyler's Test System Specifications

TweakTown award
Overall Rating94%

The Bottom Line: For non-GPU Thunderbolt 3 enclosures, there is simply no better option on the market than the Mercury Helios 3.

PRICING: You can find products similar to this one for sale below.

USUnited States: Find other tech and computer products like this over at

UKUnited Kingdom: Find other tech and computer products like this over at

AUAustralia: Find other tech and computer products like this over at

CACanada: Find other tech and computer products like this over at

DEDeutschland: Finde andere Technik- und Computerprodukte wie dieses auf

Tyler Bernath

ABOUT THE AUTHOR - Tyler Bernath

Growing up in a small farm town in northern Ohio, technology was never around unless it was in a tractor. At the early age of nine years old, my parents brought home our very first PC and I was instantly hooked and quickly learned what it meant to format a hard drive, spending many nights reinstalling Windows 95 as my parents slept. As I grew up, many things changed around me, but my love and enthusiast nature always kept my PC at my side. Eager to get deeper into technology, I started reviewing products.

We openly invite the companies who provide us with review samples / who are mentioned or discussed to express their opinion. If any company representative wishes to respond, we will publish the response here. Please contact us if you wish to respond.

Related Tags