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sfoxy

macrumors newbie
Original poster
Aug 19, 2011
28
35
The Mac Studio has 4 separate Thunderbolt buses, so I assumed that would mean each would have its own power delivery. However, I already have 2 external Thunderbolt 3 NVMe enclosures attached, and when I try to attach a 3rd, it says there is not enough power for it. I have unplugged everything else and tried just the 3 enclosures, but get the same. They are cheap Acasis enclosures, so wondered if that was the issue, or is it jus that the Thunderbolt buses share power? When I spoke to Acasis, that is what they claim, that 2 buses share power.

I know that was true on older Macs, but is it still true in the Studio? Or has anyone successfully running more than 2 Thunderbolt drives?

EDIT: Should have mentioned this is M1 Max.
 
Last edited:

OldMike

macrumors 6502a
Mar 3, 2009
537
218
Dallas, TX
This was recently discussed here:
 
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OldMike

macrumors 6502a
Mar 3, 2009
537
218
Dallas, TX
Just re-read the thread. From the following post:


It seems that it is possible to get three bust powered drives running before receiving the low power message. I am using all of my ports, but only have the bus powered enclosures hanging off of enclosures that have their own power.
 

sfoxy

macrumors newbie
Original poster
Aug 19, 2011
28
35
Just re-read the thread. From the following post:


It seems that it is possible to get three bust powered drives running before receiving the low power message. I am using all of my ports, but only have the bus powered enclosures hanging off of enclosures that have their own power.
Ah, thanks for that. I did search for Thunderbolt in titles, but not TB!
 

sfoxy

macrumors newbie
Original poster
Aug 19, 2011
28
35
Just re-read the thread. From the following post:


It seems that it is possible to get three bust powered drives running before receiving the low power message. I am using all of my ports, but only have the bus powered enclosures hanging off of enclosures that have their own power.

I just clarified my original post that I have the M1 Max which only has 4 TB ports, so that is why I am limited to 2 bus powered drives. Seems that pairs of ports are sharing power. Acasis do a powered enclosure, so may have to get that.
 

Falcon_64

macrumors regular
Oct 26, 2017
103
151
I just clarified my original post that I have the M1 Max which only has 4 TB ports, so that is why I am limited to 2 bus powered drives. Seems that pairs of ports are sharing power. Acasis do a powered enclosure, so may have to get that.
I'm the OP on the thread that @OldMike linked to. My Studio has the Ultra, that's why I'm getting one more than you are able to use with your Max. I think it's odd that, despite being two Max chips and double the TB4 ports, I don't get to use twice the number of bus powered TB devices.

After seeing your post, though, I tested on my 14" MBP. I have a M1 Pro, not Max, but TB4 ports are identical. Like you on your Max Studio, I only can use two bus powered TB externals, the third fails.
 
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