Announced at the 2017 NAB Show, the Sonnet eGFX Breakaway Box Thunderbolt-to-PCI-Express expansion system adds to the growing list of Thunderbolt3 external GPU enclosures. We were very fortunate to receive one of the first production units to review. Accompanying this enclosure was the newly released RX 580, courtesy of AMD XConnect team.
This Sonnet Breakaway Box is the third certified Thunderbolt 3 eGPU enclosure we have reviewed. The first two are tough acts to follow. The AKiTiO Node sets the bar at
$300 $245 or bust (for single I/O). The Mantiz Venus does everything we want in an all-in-one external GPU docking station. Since the first-mover advantage has been taken, how does the Sonnet distinguish itself?
Stay cool and be quiet.
|Model||350 | 550 | 350D|
|Included GPU|| ✖ | ✖ | RX580
||$249 | $349 | $699
|PSU max power||350W | 550W | 350W
|GPU max power
||300W | 375W | 225W
|Power delivery (PD)
||15W | 87W | 60W|
|TB3 USB-C ports||1|
|USB3.0 ports (+C type)
|Size (in/mm, LxWxH)
||13.38 x 7.25 x 8.00
340 x 185 x 202
|Max GPU len (in/cm)
|Updated firmware||25.2 | 25.2 | 25.1 ✔|
|TB3 cable length (cm)||50|
As external GPU gets more attention from the general public (featured on AppleInsider, iMore, and The Verge), demographics other than gamers are interested in adding external graphics cards to their workflow. The professional segment in particular is underserved. Catering to this group of buyers is highly rewarding as long as their demands are met.
Sonnet’s lineup of computer peripherals and accessories is definitely more work than play. So it’s a logical progression for Sonnet to build an external GPU solution for professionals. The criteria is straightforward; it needs to be reliable with effective cooling and no distracting add-ons, intentional or otherwise.
Priced starting at
$299 $249 for the 350W unit, the Sonnet Breakaway Box is an eGPU enclosure whose single purpose is to provide graphics performance boost through its sole Thunderbolt 3 port. For first impressions and additional photos, check out the unboxing post. The two components of this enclosure worth paying close attention to are the PSU and the main cooling fan. Both are built by Akasa, a supplier of thermal solutions to the electronics industry. The power supply is a 350W SFX unit. It’s custom-made to have one 24-pin main power cable, one 6-pin PCIe cable, and one 6-pin + 2 PCIe cable.
The 120mm fan is rated for 6.9 -16.05 dB(A), with 10 dB being the noise of a pin dropping. Airflow is routed out of the enclosure space behind the GPU and in front of the PSU. This main cooling fan is inaudible to my ears when a powerful graphics card is in use. Another cool aspect of the thermal control system is the fan bracket. It’s very sturdy which helps prevent vibration.
At the heart of this enclosure is of course the Thunderbolt 3 main board. We see an old friend with the exact layout and part number as the Mantiz eGPU board. The USB-C controller is a Texas Instrument TPS65983, which ensures compatibility with macOS. The Thunderbolt 3 controller is DSL6540 that can be flashed as new Thunderbolt firmwares become available.
The Sonnet Breakaway Box enclosure construction is different than both the AKiTiO Node and Mantiz Venus that I reviewed. It reminds me of a standard desktop tower given the similarity in materials and top cover held in place by the three thumb screws. The metal cage frame is minimal but sturdy. This construction makes the whole enclosure very light. The matte finish front fascia is made of plastic. The Sonnet logo serves as a power light when there’s connectivity with a Thunderbolt host.
There are no specifics as to the dimensions of graphic cards this Sonnet enclosure can fit. I’ve successfully installed not only the RX 580, but also the R9 Fury Nitro (12.09″ x 4.92″) and R9 Fury X with its liquid cooling components. They both work well within this box.
Testing & Benchmarks
I paired this Sonnet Breakaway Box with a Gigabyte AORUS Radeon RX 580 XTR 8G GPU. The hosts I used are:
- Dell XPS 13 9365 – dual core i7-7Y75 Kaby Lake, 16GB RAM, Intel HD 615 iGPU – Windows 10
- Alienware 13 R3 – quad core i7-7700QH Kaby Lake, 16GB RAM, GTX 1060 6GB dGPU & Intel HD 630 iGPU – Windows 10
- Apple late-2013 Mac Pro – hexa core Xeon E5, 32GB RAM, FirePro D500 dGPUs – macOS 10.12
Neither of the two Windows 10 laptops are eGPU-certified hosts. Fortunately we now have Thunderbolt 3 enclosures with high compatibility firmware, so they work with almost every Thunderbolt computer. This makes life easy in the Windows 10 environment. The AMD XConnect team has also been hard at work to keep its drivers up-to-date with the latest games and Radeon graphics cards. It was plug-and-play to get the Dell XPS and Alienware 13 R3 up and running with this Sonnet RX 580 eGPU. Below are the benchmarks:
|AMD RX 580 8GB eGPU||Dell XPS 9365||Alienware 13 R3|
|Unigine Valley||2,059 (49.2 FPS)||2,070 (49.5 FPS)|
|Unigine Heaven||1,230 (48.8 FPS)||1,267 (50.3 FPS)|
|Unigine Superposition||2,490 (18.6 FPS)||2,518 (18.8 FPS)|
|3DMark Time Spy||4,152 (27.9 FPS)||4,206 (28.3 FPS)|
|3DMark Fire Strike||12,843 (60.5 FPS)||13,079 (61.2 FPS)|
|Metro Last Night Redux||52.3 FPS||73.4 FPS|
|Rise of the Tomb Raider||51.5 FPS||56.6 FPS|
|Tom Clancy's The Division||33.7 FPS||28.8 FPS|
We have made significant progress in macOS eGPU implementation. It’s still a system hack process until Apple officially gives its blessing. With recent announcement of the completely redesigned Mac Pro in the pipeline, we hope this happens sooner rather than later.
To pair this Sonnet RX 580 eGPU with the late-2013 Mac Pro trashcan, I relied on Goalque’s trusted automate-eGPU script. The Radeon RX 580 shares the same PCI ID with its older brother, the RX 480. The same system kext edits enable all 36 CUs remain functional. Here’s a photo showing F1 2016 gameplay using this eGPU setup in macOS. The in-game benchmark scored 48 FPS on the RX 580 eGPU vs. 21 FPS on the Mac Pro’s discrete D500 GPU.
I’ve been using this Sonnet Breakaway + RX 580 eGPU setup for the past week. It has been a reliable, capable and quiet workhorse with the Late 2013 Mac Pro trashcan. The enclosure has been housed under the desk, hidden from view. Many times I’ve forgotten it’s even there.
The Sonnet Breakaway is like your accountant. He may not be the most fun or flashy. But when the IRS comes knocking, he’ll crunch the numbers like nobody’s business to get the job done. All the while being calm and collected.
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