[eGPU]: Sonnet Breakaway 550W with Vega 64

[arctair]

Confused: If an AMD Vega 64 is rated to use 295W, why is it "incompatible" with a 550W Sonnet box? It is something obvious like it needs some breathing room for power spikes? If that's the case, then 85W is enough room (as the AMD Vega 56 is considered compatible; it's rated to use 210W.

(These ratings all come from https://www.tomshardware.com/reviews/gpu-hierarchy,4388.html; the compatibilities come from https://support.apple.com/en-us/HT208544)

 

[ruslan120]

Good question, I’ve wondered this myself as well.

I am running a 5700 XT on a 350w with no issues.

That being said I have not tried charging a laptop using USB power delivery, which I think is the reason.

I am also planning on upgrading to a 550 W power supply soon.

 

[Erehy Dobon]

Confused: If an AMD Vega 64 is rated to use 295W, why is it "incompatible" with a 550W Sonnet box? It is something obvious like it needs some breathing room for power spikes? If that's the case, then 85W is enough room (as the AMD Vega 56 is considered compatible; it's rated to use 210W.

(These ratings all come from https://www.tomshardware.com/reviews/gpu-hierarchy,4388.html; the compatibilities come from https://support.apple.com/en-us/HT208544)

AMD's own recommendations for their reference Vega 64 card is a 750W power supply. Of course that assumes that it will be installed in a PC with components that also draw power (motherboard, CPU, RAM, storage, case fans, etc.).

The guys over at VideoCardz suggest a 600W PSU.

It is likely that Apple and Sonnet tested them out and came to the conclusion that the 550W PSU was cutting it too close to the limit. The Vega 64 draws more power when it first starts and is still cold according to the TH review (pages 17 and 18).

 

[mmomega]

I have a Vega64 watercooled card in a Sonnet Breakaway box and have been running it for around for 2 and a half years.
Another Vega64 Strix in a Razer Core enclosure with 600W power supply, then a Radeon 7 in another Breakaway box.
I have had absolutely no issues with the eGPU or card working fine, the only issues over the years has been occasional driver issues in the middle of beta macOS updates.
If I get some time later I can put the eGPU on a Kill-a-Watt meter running a worst case scenerio stress test or benchmark and show the actual power usage.

On some of the sub-600W power supplies earlier on, the manufacturers were cautious with their recommendations because many people would also be drawing power to charge their laptop as well as GPU usage and those particular boards did not delivery very much power delivery.
Putting a larger power supply will not change the power delivery, it is a limit of those boards on those model eGPU's. So if you are wanting max power delivery and GPU usage, choose an enclosure with a higher rated power delivery.
If it will be connected to a desktop or the laptop is under it's own power you're fine. Even with the low power delivery you're fine, the laptop will just not be able to get enough power to keep it charged for a sustained amount of time.

 

[Erehy Dobon]

It's worth pointing out that PSUs have a sweet spot in terms of load efficiency, maybe around 50-60% during normal usage and around 75-80% maximum/peak usage.

I believe the two existing Sonnet eGPX Breakaway Boxes provide 60W notebook charging power over the Thunderbolt 3 cable. That should be accounted for when researching external GPU enclosures and power availability.

 

[mmomega]

There are 2 different 350W Breakaway Boxes.
1 delivers 15 watts power delivery, the other delivers 60w.
The 550W and 650W deliver 87Watts.

 

[Erehy Dobon]

We are both wrong.

The 650W box provides 100W notebook charging per the Sonnet website. The 550W box provides 87W notebook charging.

The 350W models have been discontinued for quite a while, maybe nearly two years. They are no longer marketed on the Sonnet website so it's a moot point anyhow.

Besides, the OP is focused on the Vega 64, not some low-end GPU so any discussion about the discontinued 350W model is particularly irrelevant in this thread.

I'm not surprised Sonnet discontinued the 350W model. Judging by price-performance return, there's very little sense spending ~$300 on a 350W enclosure to shove in mid-range graphics card.