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Sonnet eGFX Breakaway Box 550 (GPU-550W-TB3)
Sonnet

Sonnet eGFX Breakaway Box 550

Expert rating6 / 10

External GPU EnclosuresView on sonnettech.com
Connection:
Thunderbolt 3
PSU:
550W
Host Charging:
87W
GPU Fit:
Double-wide

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Disclaimer: The price and specification of the given product may differ from the actual product. Please confirm on the retailer's website before buying.

Manufacturer: Sonnet Last updated: 2026-09-12

Where to buy

Sonnet eGFX Breakaway Box 550 (Thunderbolt 3 / 550W PSU / 87W Laptop Charging / Single-Wide to Double-Wide GPU) Review

If you're looking at the Sonnet eGFX Breakaway Box 550, one of Sonnet's earliest Thunderbolt 3 enclosures, and wondering how it stacks up to their newer boxes,

it's a perfectly usable 550W enclosure for older RTX 20-series or GTX 10-series cards, but Sonnet's own 650 model gives you 100W more PSU headroom for barely more money, so we'd point most buyers there instead unless this one is on clearance.

What It Actually Is

Launched in late 2017, the Breakaway Box 550 was one of Sonnet's first Thunderbolt 3 eGPU enclosures, built around a 550W internal supply with 87W of USB-C laptop charging and room for double-wide cards up to 300mm. It shares the same vented aluminum design language as every later Sonnet box.

Comparison to Alternatives

The Sonnet eGFX Breakaway Box 650 is the direct step up, same chassis and charging spec but 100W more PSU headroom for a small price difference, making it the better buy for most people today. Against the Sonnet eGFX Breakaway Puck, the 550 is a full modular enclosure rather than a pre-installed compact GPU, so it suits anyone who wants to choose and later swap their own card.

Specifications

Identity

BrandSonnet

Connectivity

Connection StandardThunderbolt 3
Extra PortsNone onboard beyond the GPU's own outputs

Power & Compatibility

PSU Wattage550 W
Host Power Delivery87 W
Max GPU Length300 mm
Cooling TypeActive Fan
ModeleGFX Breakaway Box 550
GPU CompatibilityGTX 10-series through RTX 20-series and equivalent AMD cards, double-wide
PriceLaunched around $399 (2017)

Expert Review

Reviewed by Burooj Alam. Rated by us, not by users.

Expert rating6 / 10

A solid early Sonnet box, but the 650 offers more headroom for little extra cost.

Best for

  • Budget builds running GTX 10-series or RTX 20-series double-wide cards
  • Buyers who find it discounted versus the newer 650
  • Mac users wanting Sonnet's certified eGFX driver support on Thunderbolt 3

Not for

  • RTX 30-series or newer cards that want more PSU headroom
  • Anyone who can spend a little more for the Breakaway Box 650's extra 100W
  • Builds needing more than 300mm of card clearance

FAQs

What are the key specifications of the Sonnet eGFX Breakaway Box 550 (Thunderbolt 3 / 550W PSU / 87W Laptop Charging / Single-Wide to Double-Wide GPU)?

The Sonnet eGFX Breakaway Box 550 (Thunderbolt 3 / 550W PSU / 87W Laptop Charging / Single-Wide to Double-Wide GPU) is a eGPU enclosure from Sonnet. Key specs: Connection Standard Thunderbolt 3, PSU Wattage 550, Max GPU Length 300, Host Power Delivery 87, Extra Ports None onboard beyond the GPU's own outputs.

Who is the Sonnet eGFX Breakaway Box 550 (Thunderbolt 3 / 550W PSU / 87W Laptop Charging / Single-Wide to Double-Wide GPU) best suited to?

It suits budget builds running gtx 10-series or rtx 20-series double-wide cards, buyers who find it discounted versus the newer 650, mac users wanting sonnet's certified egfx driver support on thunderbolt 3.

What are the drawbacks of the Sonnet eGFX Breakaway Box 550 (Thunderbolt 3 / 550W PSU / 87W Laptop Charging / Single-Wide to Double-Wide GPU)?

It is a poor fit for rtx 30-series or newer cards that want more psu headroom, anyone who can spend a little more for the breakaway box 650's extra 100w, builds needing more than 300mm of card clearance.

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