• Overview
  • Tech Specs
  • Reviews
Connect a High-Performance Graphics Card
or Other Bandwidth-Hungry PCIe Card to a
Thunderbolt™ 3 Equipped Computer

Thunderbolt 3 Notebooks

Sonnet’s eGFX Breakaway Box, a Thunderbolt 3 to PCIe card expansion solution, supports any Thunderbolt compatible PCIe card, but is designed specifically for bandwidth-intensive graphic video cards. The Breakaway Box enables all the popular GPU cards that support connecting to a computer over Thunderbolt such as AMD Radeon® R9 and RX and NVIDIA® GeForce® GTX7, 9 and 10 series, providing GPU support for computationally-intensive applications and games.

Supports AMD XCONNECT Technology

Graphic Intensive Gaming

Gamer with eGFX Breakaway BoxThere’s no need to carry a heavy and expensive gaming laptop to have a great gaming experience—just plug in a Breakaway Box and add the GPU power you want when you need it! By delivering much higher frame rates for smooth game play, the Breakaway Box is ideal for enabling graphic-intensive gaming on computers (such as thin/light notebooks) that otherwise would not be able to produce an acceptable gaming experience. When used with computers that properly support eGPUs, accelerated graphics can either be displayed on your notebook’s own display panel or on external monitors. And, unlike with gaming laptops, when the next generation of GPUs rolls around and you are ready for another performance boost, simply upgrade the GPU card—nobody should have to replace their computer just to keep up with the latest in GPU technology.

Ready for Work, Coolest & Quietest eGFX Graphics Card Box on the Market

PCIe Card and Notebook Icons

In addition to eGPU cards, the Breakaway Box supports every other Thunderbolt-compatible PCIe card, regardless of the card's length or width—its single x16 PCIe 3.0 slot easily accommodates full-length cards such as the RED Rocket-X or AVID Pro Tools|HDX.
The Breakaway Box’s single-port 40Gbps Thunderbolt 3 interface ensures the full 2750 MB/s of PCIe bandwidth(1) is dedicated to the installed card.

eGFX Breakaway Box Internal Fan

The Sonnet eGFX Breakaway Box is the coolest and quietest eGFX box on the market—with its large variable-speed, temperature-controlled fan that quietly and effectively cools the installed card, the Breakaway Box can be comfortably used in noise-sensitive working environments.

Key Features

Connects High Performance GPU Cards to Computers with Thunderbolt 3 Ports—Connects a supported GPU card to your eGFX-compatible computer with Thunderbolt 3 ports

Supports Cards With Popular GPU Chipsets—Includes AMD Radeon R9 and RX and NVIDIA GeForce GTX 7, 9 and 10 series

x16 PCI Express 3.0 slot—Supports up to full-length, full-height, single- or double-width card

Supports Other Thunderbolt™ 3 Compatible PCIe Cards—Perfect for full-length cards such as the RED ROCKET-X or AVID Pro Tools|HDX

40Gbps Thunderbolt 3 Interface with One Thunderbolt 3 (USB-C) Port—Ensures full 2750 MB/s of PCIe bandwidth(1) is dedicated to the installed card

Available with 350W or 550W Power Supply—Model with 350W power supply has one 8-pin & one 6-pin auxiliary power connector and delivers 15W of upstream power; model with 550W power supply has dual 8-pin connectors and can also deliver 87W upstream power to charge your computer

Quietest eGFX System Available—Large built-in, variable-speed, temperature-controlled fan quietly and effectively cools the installed card

Thunderbolt Certified for Mac & Windows(4)


eGFX Breakaway Box with Mac Pro In Video Editing Studio

For Media Professionals

In today’s 4K workflows, harnessing the computational engine in today’s GPU cards is essential to keeping up with on-set and post production timelines. The eGFX Breakaway Box is ideal for supporting the acceleration of special effects, animation, color grading, rendering, and editing.

40Gbps Thunderbolt 3 Performance

Thunderbolt 3 Port IconThunderbolt 3 is a leap forward in every way. Whether you’re editing 4K video at high frame rates or blasting aliens out of the sky, you can now transform your notebook into a true desktop experience. With up to 2750 MB/s available bandwidth(1), the Breakaway Box exploits its 40Gbps Thunderbolt 3 interface to offer the best-possible eGPU experience, or handle the most demanding, highest performance PCIe cards.

eGFX Breakaway Fox Front ShotAvailable with 350W or 550W
Power Supply

Sonnet offers two eGFX Breakaway Box models to choose from—the eGFX Breakaway Box 350 and eGFX Breakaway Box 550—enabling you to select one best suited to your needs. The eGFX Breakaway Box 350 includes 8-pin plus one 6-pin auxiliary power connectors, supports cards requiring 300W or less power, and provides 15W of upstream power. The eGFX Breakaway Box 550 includes dual 8-pin auxiliary power connectors, supports cards requiring 375W+ of power, and provides 87W of upstream power, useful for charging your notebook computer. Both models include a 0.5-meter Thunderbolt 3 (40Gbps) cable to connect the box to your computer. Whichever model you choose, the Breakaway Box is Thunderbolt Certified for Mac and Windows.

350 WATT & 600 WATT Icons

eGFX Breakaway with Notebook & Three Monitor Setup

Fire Power to Drive Multiple Displays and Charge Your Notebook(5)

Part No.  
GPU-350W-TB3Z eGFX Breakaway Box Thunderbolt 3™ to eGPU Expansion System w/350W Power Supply
GPU-550W-TB3 eGFX Breakaway Box Thunderbolt 3 to eGPU Expansion System w/550W Power Supply
Warranty 1-year
Form Factor Desktop Thunderbolt 3 to PCIe card expansion system
External Connectors
  • One Thunderbolt 3 (USB-C)
  • Power (C14-type)
Internal Connector
(Part No. GPU-350W-TB3Z)
  • One 8-pin plus one 6-pin PCIe power connector
  • Supports up to 300W PCIe card
Internal Connector
(Part No. GPU-550W-TB3)
  • Two 8-pin PCIe power connectors
  • Supports 375W+ PCIe card
Expansion Slot One PCIe 3.0 slot
  • x16 Mechanical
  • x4 Electrical (Thunderbolt 3 Spec)
PCIe Card Supported One full-length, full-height, double-width PCIe card
Liquid Cooling Supports 120mm Water Block Coolers
Power Supply
(Part No. GPU-350W-TB3Z)
Universal 350W, 110-240V AC, 50-60 Hz
Power Supply
(Part No. GPU-550W-TB3)
Universal 550W, 110-240V AC, 50-60 Hz
Operating Temperature

0˚C to 35˚C (32˚F to 95˚F)

Dimensions (WxDxH) 7.25 x 13.38 x 8 in. (18.5 x 34.0 x 20.2 cm)
Weight   7.1 lbs (3.2 kg)
RoHS Compliant Yes
Package Contents
  • eGFX Breakaway Box system
  • Power cord
  • 0.5-meter Thunderbolt 3 (40Gbps) cable
  • Documentation

Note: PCIe cards sold separately


Specifications subject to change without notice.






Windows Compatibility

Windows PC with a Thunderbolt 3 port (GPU card requires an eGFX-enabled Windows PC)

64-bit Windows 10, version 1607 or later

Mac Compatibility

Mac with Thunderbolt 3 ports

Mac with a Thunderbolt 2 or Thunderbolt port with an Apple Thunderbolt 3 (USB C) to Thunderbolt 2 Adapter

macOS 10.12.5+

GPU card use see note 4

Technical Notes

  1. While the eGFX Breakaway box features a 40Gbps Thunderbolt 3 interface, some computers equipped with Thunderbolt 3, such as the Dell Precision 3510 and the Alienware 13 R2, use an implementation of Thunderbolt 3 technology that limits PCIe performance to 20Gbps. The MacBook Pro (13-inch, Late 2016, Four Thunderbolt 3 Ports) also has this limitation in the two right-hand Thunderbolt 3 ports, while offering full performance from the left-hand ports. Full performance also requires the use of the included Thunderbolt 3 (40Gbps) cable, or other Thunderbolt 3 (40Gbps) cables; look for the Thunderbolt icon AND the number 3 on the connector housings to identify these cables.
  2. Choose eGFX Breakaway Box model that supports the power requirement of the chosen card.
  3. List of supported eGFX-enabled Windows computers available soon. Windows computers require the latest firmware (BIOS) and other drivers.
  4. Other than macOS High Sierra Developer Beta, macOS does not yet support connection of GPU cards over Thunderbolt and GPU card drivers are not yet officially Thunderbolt compatible for macOS.
  5. The eGFX Breakaway Box 550 includes provides 87W of upstream power, useful for charging your notebook computer.

Mac LogoWindows Logo PCI Express Logo
PSE & Wheele Trash Can IconsroHS Logo



GPU Cards Support(2)

AMD GPU Cards Supported(3)

AMD Radeon RX 570 AMD Radeon R9 Nano
AMD Radeon RX 560 AMD Radeon R9 300 Series
AMD Radeon RX 480 AMD Radeon R9 290X
AMD Radeon RX 470 AMD Radeon R9 290
AMD Radeon RX 460 AMD Radeon R9 285
NVIDIA GPU Cards Supported(3)(4)    
NVIDIA GeForce GTX 1080 Ti NVIDIA GeForce GTX 960
NVIDIA GeForce GTX 1080 NVIDIA GeForce GTX 950
NVIDIA GeForce GTX 1070 NVIDIA GeForce GTX 750 Ti
NVIDIA GeForce GTX 1060 NVIDIA GeForce GTX 750
NVIDIA GeForce GTX 980 Ti  
NVIDIA GeForce GTX 980  
Other PCIe Cards

PCIe cards listed on our supporting PCIe Card Thunderbolt Compatibility Chart and as specified by card manufacturers

  Sonnet eGFX Breakaway Box Reviews
Bare Feats

What Did We Learn?

The eGFX Breakaway Box with the NVIDIA GeForce GTX 1080 Ti and connected to a Mac can speed up multi-GPU rendering in apps like Blender and Resolve (Noise Reduction render on the fly during playback); add CUDA support to your AMD equipped Macs thereby enabling 'CUDA only' apps like Octane Render to function and 'CUDA capable' apps like Blender to function faster than the "OpenCL only" AMD GPUs provided by Apple; provide a surge in the OpenCL render rate as well as combine with factory AMD GPUs to double the render rate; and triple and quadruple the frame rates of OpenGL apps like Valley and Tomb Raider.

Sonnet Technologies came up with their own unique eGPU design. It includes all the best eGPU features such as quiet exhaust fan and the ability to send power to your 2016 MacBook Pro laptop. An nice touch was the PCIe Card Bracket Locking Plate.

Unlike other eGPUs, the eGFX Breakaway Box does not require you to run the tb3-enabler in order to be detected as a supported Thunderbolt device.

Read Full ReviewLink


Sonnet Breakaway Box 350 Review – It's Cool to Be Quiet

Priced at $299, 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.

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…

Read Full ReviewLink



Ideal for Accelerating

• Special effects
• Animation
• Color grading
• Rendering
• Editing

Also Ideal for Enabling Graphic Intensive Gaming
on Non-Gaming Computers:

• Enables high frame rate gaming with thin/light notebooks
• Accelerated graphics on notebook display or external display
• No need to carry around a heavy/expensive gaming
   laptop—plugin GPU power when you need it

 PCIe cards and computer hardware shown in photos for illustration purposes; items sold separately. Thunderbolt and the Thunderbolt logo are trademarks
of Intel Corporation in the U.S. and/or other countries. Other names and brands may be claimed as the property of others.
See Tech Specs Tab for footnotes