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OWC Mercury Helios 3 vs Sonnet eGFX Breakaway Box 350: Comparison
OWC Mercury Helios 3 vs Sonnet eGFX Breakaway Box 350: the host power delivery difference
On host power delivery the spread is 82%, OWC Mercury Helios 3 85 W against Sonnet eGFX Breakaway Box 350 15 W, so OWC Mercury Helios 3 takes it. OWC Mercury Helios 3 also leads on max gpu length, 290 mm on the OWC Mercury Helios 3 versus 220 mm on the Sonnet eGFX Breakaway Box 350.
Who each one is for
The OWC Mercury Helios 3 is the one to take for simple, no-frills dual-slot GPU builds under 400W, though it is the wrong buy for cards that need more than 290mm of clearance and Windows users wanting extra I/O built into the box. It is equally the pick for Mac users who find a used unit cheap and just need a bare Thunderbolt 3 enclosure. It is not the one for anyone buying new, since the Mercury Helios FX replaced it with more PSU headroom. The Sonnet eGFX Breakaway Box 350 suits buyers who specifically want a quieter Noctua-fan enclosure and compact desk setups where a full double-wide box is overkill, though it is not built for buyers wanting real laptop charging power (only 15W here) and anyone chasing high frame rates on a modern RTX card. It also earns its place with video editors running single-slot acceleration cards for Avid HDX or similar workflows. It is the wrong buy for any double-wide gaming GPU, since the chassis physically won't fit one.
Frequently asked questions
Do the OWC Mercury Helios 3 and Sonnet eGFX Breakaway Box 350 differ on cooling type?
Yes. Cooling Type reads Active Fan on the OWC Mercury Helios 3 versus Active, ultra-low-noise Noctua fan on the Sonnet eGFX Breakaway Box 350.
Is the Connection Standard the same on the OWC Mercury Helios 3 and Sonnet eGFX Breakaway Box 350?
It is. Both are listed at Thunderbolt 3, so it is not a reason to pick one over the other.
Specs and benchmarks
Brand
- OWC Mercury Helios 3
- OWC
- Sonnet eGFX Breakaway Box 350
- Sonnet
Connection Standard
- OWC Mercury Helios 3
- Thunderbolt 3
- Sonnet eGFX Breakaway Box 350
- Thunderbolt 3
Model Number
- OWC Mercury Helios 3
- Mercury Helios 3
- Sonnet eGFX Breakaway Box 350
- eGFX Breakaway Box 350
Extra Ports
- OWC Mercury Helios 3
- None onboard beyond the GPU's own outputs
- Sonnet eGFX Breakaway Box 350
- None onboard beyond the GPU's own outputs
PSU Wattage
- OWC Mercury Helios 3
- 400 WBest
- Sonnet eGFX Breakaway Box 350
- 350 W-12%
Host Power Delivery
- OWC Mercury Helios 3
- 85 WBest
- Sonnet eGFX Breakaway Box 350
- 15 W-82%
Max GPU Length
- OWC Mercury Helios 3
- 290 mmBest
- Sonnet eGFX Breakaway Box 350
- 220 mm-24%
Cooling Type
- OWC Mercury Helios 3
- Active Fan
- Sonnet eGFX Breakaway Box 350
- Active, ultra-low-noise Noctua fan
GPU Compatibility
- OWC Mercury Helios 3
- GTX 10-series through RTX 20-series, dual-slot cards
- Sonnet eGFX Breakaway Box 350
- Single-slot cards, GTX 1050 Ti to mid-range single-slot workstation and gaming cards
Price
- OWC Mercury Helios 3
- Launched around $299 (2018)
- Sonnet eGFX Breakaway Box 350
- Launched around $299 (2017)
Which one should you pick?
Choose OWC Mercury Helios 3 if you want the higher PSU wattage (400 W vs 350 W), the higher host power delivery (85 W vs 15 W) and the higher max GPU length (290 mm vs 220 mm).
Choose Sonnet eGFX Breakaway Box 350 if you already have it on hand or find it at a lower price.
Price comparison
| Retailer | OWC Mercury Helios 3 | Sonnet eGFX Breakaway Box 350 |
|---|---|---|
| Consumercarts listing | $299.00 View on Consumercarts listing | |
| Full Compass | $299.00 View on Full Compass |
Disclaimer: The price and specification of the given product may differ from the actual product. Please confirm on the retailer's website before buying.
Verdict
OWC Mercury Helios 3
6 / 10 Expert Rating
Solid basic Mac eGPU box, superseded by the Helios FX which OWC still actively sells.
Sonnet eGFX Breakaway Box 350
6 / 10 Expert Rating
A niche but well-executed pick for single-slot cards and quiet operation, not for gaming-class GPUs.