Sonnet Breakaway Box Review – It’s cool to be quiet

eGPU Reviews, External GPU 48 Comments


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.

Hardware Specifics

sonnet breakaway box fan and psu

Sonnet Breakaway Box Cooling Fan + PSU

Specifications  compare 
Model 350 | 550 | 650 | 350D | 650
Included GPU  ✖  |   ✖  |   ✖  | RX580 | Vega64
Price US$
$229 | $329 | $449 | $579 | $1299
PSU location-type
PSU max power 350W | 550W | 650W | 350W | 650W
GPU max power
300W | 375W | 475W | 225W | 475W
Power delivery (PD)
15W | 87W | 87W | 60W | 87W
USB-C controller
TB3 USB-C ports 1
USB3.0 ports (+C type)
Ethernet port
SATA port
Size (in/mm, LxWxH)
13.38 x 7.25 x 8.00
340 x 185 x 202
Max GPU len (in/cm)
Weight (kg/lb) 3.20/7.10
Updated firmware 25.2 | 25.2 | 25.2 | 25.1 | 25.2 ✔
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.

Sonnet Breakaway Box component view

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.

Top view of Radeon R9 Fury X with liquid cooling lines, fan, and radiator

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 eGPUDell XPS 9365Alienware 13 R3
Unigine Valley2,059 (49.2 FPS)2,070 (49.5 FPS)
Unigine Heaven1,230 (48.8 FPS)1,267 (50.3 FPS)
Unigine Superposition2,490 (18.6 FPS)2,518 (18.8 FPS)
3DMark Time Spy4,152 (27.9 FPS)4,206 (28.3 FPS)
3DMark Fire Strike12,843 (60.5 FPS)13,079 (61.2 FPS)
Metro Last Night Redux52.3 FPS73.4 FPS
Rise of the Tomb Raider51.5 FPS56.6 FPS
Tom Clancy's The Division33.7 FPS28.8 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.

Late 2016 Mac Pro + Breakaway Box + LG Monitor


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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Would this eGPU work in Bootcamp with iMac 5K + TB3>2TB adapter? I’ve heard in the forums here that certain eGPUs wouldn’t, I’d like to know if you can get it to work in Bootcamp + external monitor?


I already bought an Akitio Note; I should be waited, because now we have better options. Akitio Note has poor quality in some components (Cooler and Power Supply).

Himanshu Nanda

Hi. I intend to buy an 8core Mac Pro with d700’s and 64 gb ram. For video graphics. Software: FCPX, Adobe (AE & PP) and Autodesk Flame. Will egpu help. What egpu and what card do you suggest. Need stability and performance. Price no issue.


Would this PSU be enough to power a GTX 1080 or 1080 TI?


Check if your GTX1080Ti has a 6+6 pin (225W) or 6+8pin (300W) PCIe power plugs. This enclosure can power both. It cannot power 8+8pin (375W) cards.


Sonnet has published a comprehensive list of compatible graphics cards at


Is it not compatible with Nvidia Geforce GTX 960 4gb DDR5? It´s not in the list and I don´t know if it can be or not

Himanshu Nanda

Thank you so much for your advise.
Will the titan xp be stable in performance or the older 980 ti.
Also I hope having an egpu will not effect the performances of the stock Mac Pro.


May I ask where can I get the motherboard only? I would like to build my own box. Much appreciated.


Hi. What GPU you can recommend for FCPX, DaVinci and 3D Modeling and Rendering with Luxology Modo or Blender? I’m interested in updating my nMP 2013 with 2xD300.


Any idea when this or the 500 watt version will be made publicly available to purchase? I can only see sites offering pre-orders…but no official release date


Will this enclosure work with a 2016 15″ Macbook Pro to the built in display?
I want to get a new Macbook Laptop, get better Adobe Premiere rendering speeds at home & be able to play games at decent fps in MacOS & Windows via Bootcamp.
Will the Breakaway Box paired with a RX 580 do the job?


”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.”

And it has happened! 🙂


Will work with- Apple late-2013 Mac Pro core Xeon E5, 32GB RAM, FirePro D500 + Thunderbolt Display 27?


can I install a liquid cooled GPU in it?


Can it hold an AMD Radeon Vega Frontier Edition liquid cooled GPU? Is there a tutorial on how to remove the 120mm case fan and mount the radiator? Does Mac 10.13 support AMD Radeon Vega Frontier Edition?


I suggest waiting a bit longer for Vega RX (or whatever it will be called). Frontier was never meant for eGPU use; even though it does fit, it will require power supply change.


You mention plug and play implantation in Windows but I hear Bootcamp isn’t as simple, despite still being Windows? Or am I wrong?


How heavy is it with/without a GPU in it? Is it light/small enough to be just about portable along with a laptop? (I’m guessing a rucksack or similar would be needed)


In the wait for the real MacPro, I got the latest high end iMac 2017. I wonder, could I use an AMD Radeon Vega Frontier Edition with an eGPU on my iMac to power Davinci Resolve?


Are the fans running when the Thunderbolt host is not connected?


Posted by: Anonymous
can I install a liquid cooled GPU in it?

Yes you can 🙂
But not in 350W version. Liquid cooled GPU assumes high power consumption. You can, however, easily upgrade the power supply to much higher power – just need to make sure it is SFX format


Will this work running bootcamp on a new MacBook pro?


I am thinking of getting one of these but I need to figure out how to squeeze it into a crowded edit workspace.  How hot can the exterior of the case get when under heavy use?


I’d be interested in a version without a PSU, as I’d rather replace it with a Corsair fully-modular SF600, which looks like it would fit.

Cristian Zantedeschi

HI, do you think this cabinet will work with Macbook TB3 & MSI GeForce GTX1060 Gaming X 6G 6 GB OC High End ?

( with Tensorflow )

toke lahti

I’m trying to choose between this and Razer Core X.
What kind of fan Sonnet’s 550W PSU has?


The same logic is used in the 650W model as in the 550W? Thank you.


Have had the same setup which was working great, sadly the logic board on the 350DE seemed to have gone south just about 3 weeks after the manufacturer’s 1 year warranty expired. Proceeded to contact Sonnet CS for guidance, after double checking my troubleshooting steps it became obvious that it was the logic board that was faulty. I inquired about purchasing just the logic board that contains the PCIE/TB components. Was forwarded to the RMA department after proving the serial number for the 350DE. The RMA department informed me that the logic board is not sold separately and that I… Read more »


Does board have aditional pins for RGB Fan? I would like to buy Breakaway and replace Fan with AKASA Vegas R7 RGB LED for example, but I would like to know if board even has pins for it.

John Chaney

Yep pretty sure it does