[EN] Review – Sonnet eGFX Breakaway Box

Review of the Thunderbolt 3 eGPU dock Sonnet eGFX Breakaway Box

Have you bought ultrabook or miniPC and would like to play PC games? You might have already figured out that integrated graphics are good enough for video playback or playing older PC game titles which are not very demanding. But what if you want to play new AAA titles with realistic graphics? Well, you are most probably out of your luck. Or are you? If your device has USB-C Thunderbolt 3 port, all is not is lost. You could get an eGPU dock such as the Sonnet eGFX Breakaway Box which we will review today.

The dock is packed in a box with a nice drawing of the dock itself. Inside of the package we find the dock, clear and easy to read instructions, power cable and a 0.5-meter long Thunderbolt 3 cable.

On the back side of the box you can find some basic information such as this is the eGFX Breakaway Box 350 with 6+2 and 6-pin power cables.

Let’s have a look on the dock itself. It is made out of matte black aluminium so it looks and feels very premium.

On both sides we can find ventilation for graphics card and power supply. The left opening is larger as it’s used as intake to the graphics card. The right hole exhausts hot air out of the dock thanks to the 120 mm Akasa fan.

The top and bottom don’t have any ventilation. The dock is equipped with rubber feet so it won’t move or scratch your desk or furniture.

On the front there is the Sonnet S logo which lights up in blue when the dock is active. In the back you can find the PSU, a single Thunderbolt 3 port, and space for a two slot GPU.

The dimensions of the dock are 340 x 185 x 202 mm, and it weighs 3,2 kg. The dock is quite large and heavy, and it takes a lot of space on the desk too.

If you want to get inside of the dock you need to unscrew screws on the back and push the metal body backwards.

The whole function of the dock is managed by this little board. We can find one PCIe 3.0 x16 slot, a 24-pin connector for powering the board, and two 4-pin connectors for fans.

The dock is powered by custom made Akasa PSU with power output of 350 W. It has only a 24-pin main cable and the already discussed 6+2 and 6-pin power cables for the GPU. It can support GPUs with up to 300 W power consumption (equivalent of 500 W for whole PC build). It can even charge your notebook with up to 15 W.


In September we can expect the eGFX Breakaway Box 550 with bigger power supply to be available. It has two 8 pins (6+2) and support for up to 375 W graphics cards and 87 W charging.

UPDATE November 2017: eGFX Breakaway Box 550 is available now.

The size of the dock has its purpose. It is big enough to support a full-size two-slot GPU. We have tested the dock with MSI GTX 1060 Armor 3G, which fits without any problems and plenty space to spare. There should be no problem with usage of AiO cooled GPUs, you just need to replace the Akasa fan with the AiO radiator.


Now, when we have shown you the design, build quality and internals of the eGFX Breakaway Box there is only one thing left – test it in real life. What performance advantage can this dock bring if you use it with your ultrabook or miniPC? Should you even consider it as an option?
For testing purpose we have used 3D Mark Firestrike and GTA V. The benchmark and game has been played on MSI GTX 1060 Armor 3G, which represents mainstream in current GPU market. The dock was connected to:

Intel Skull Canyon NUC6i7KYK – i7 6770HQ, quad-core, 3,4 GHz, Intel Iris Pro 580, 32 GB RAM

Lenovo X1 Carbon 5th gen – i5 7200U, dual-core, 3,1 GHz, Intel HD 620, 8 GB RAM


Let’s have a look what performance difference does the eGFX Breakaway Box with GTX 1060 deliver.

On the X1 Carbon we can see 10 times the combined score in Firestrike. The total score is almost 8 times the one achieved with integrated graphics!

The NUC behaved very similarly, but we have to mention that the Iris Pro 580 integrated graphics offer twice the performance of the X1 Carbon’s HD 620. Despite that we can see 10 times the graphics score in Firestrike again, but only 5,5 times improvement in combined score. The total score has increased 5 times.


The second test was performed with the popular AAA title GTA V which was set to Full HD resolution and Normal settings. We could have used High or Very High graphics, but the results on integrated graphics would be bad and misleading. The Normal settings allowed use to see real data from integrated graphics, and we could compare them with the GTX 1060 in the eGFX Breakaway Box.

Once again we can see that the NUC is twice as powerful as the X1 Carbon thanks to the  Iris Pro 580 graphics. However none of the integrated graphics could match the combination of GTX 1060 and eGFX Breakaway Box. The FPS on X1 Carbon has grown 5 times. What’s interesting is that the average frame rate of 93 FPS is very close to the maximum frame rate of 104 FPS. We can see CPU bottleneck here since the dual core CPU isn’t powerful enough to use all the potential of the GPU

In the case of NUC with its more powerful and faster CPU, the situation is different.  The FPS have grown 4 times, but we hit the limit of the GPU this time. Nonetheless the FPS increase in both cases is huge. If we look at the X1 Carbon, there is a day and night difference,  because with the integrated graphics GTA V is unplayable. Thanks to the eGFX Breakaway Box you could play the game on a thin and light business ultrabook, which was unthinkable till now.


On the manufacturer’s website you can find the list of compatible graphics cards and devices that support connection to the eGFX Breakaway Box. In a short, supported cards are Nvidia GTX 9th and 10th series, Titan series and AMD 500, 400 and 300 series as well as some models from 200 series, R9 Nano and R9 Fury. The list of supported devices contains mostly Windows notebooks, but you should be able to connect the dock to Apple Macbook from 2016 and 2017 with Thunderbolt 3 ports. We will work closely with the manufacturer to make the list of supported devices longer and you can expect more articles about this dock in future.

Price and availability

The main disadvantage of Thunderbolt 3 accessories in general is the cost. The first eGPU Thunderbolt 3 dock which was introduced is Razer Core with price tag of 500 USD (without VAT). This year more affordable solutions are coming to market and Sonnet eGFX Breakaway Box 350 is one of them. The official price tag is 300 USD (without VAT) which makes it one of the cheapest eGPU docs on the market. There isn’t a single reseller in Slovakia that offers this dock, but you can purchase it from our Czech brothers for 9999 CZK, which is approximately 380 EUR. The more powerful model Breakaway Box 550 costs a little bit more, more specifically 11 500 CZK, which equals to 440 EUR. The dock is offered by sellers from Poland, Austria, Germany, Great Britain and other EU countries as well.


Sonnet eGFX Breakaway Box
9.3 Hodnotenie redakcie

build quality
ease of use



Sonnet eGFX Breakaway Box is currently one of the most affordable Thunderbolt 3 eGPU docs. Despite that it offers excellent build quality, great compatibility with graphic cards and Thunderbolt 3 clients as well as a sophisticated cooling. The only disadvantage might be complicated availability in Slovakia.


Sonnet eGFX Breakaway Box got our gold award for great build quality, wide compatibility and relatively affordable price.


We thank Sonnet for providing us with review unit of eGFX Breakaway Box and companies MSI for graphics card GTX 1060 Armor 3G and Lenovo for ThinkPad X1 Carbon.


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