Why can't I use all 4 Thunderbolt ports on my Mac Studio Max (M2 version)?

I have the same situation with a Mac Studio M2 Max and 1x OWC Envoy Pro FX, 3x Samsung X5, and 1x SanDisk Professional Portable SSD.

Maximum 2 SSDs can connect directly to the Mac Studio Thunderbolt port (irrelevant of the combination). If I try to connect a third one, I get the "Accessory Needs More Power" notification in macOS and it doesn't mount. The only way to make the third SSD mounting is through my external LaCie d2 Thunderbolt 3 10TB HDD which has 2 Thunderbolt ports (and a power adapter).

For a professional grade workstation, this is very unsatisfactory.

Given the variety of external SSD storage marks and models involved in all the posts in this thread, it is most likely be an issue on Apple side or the Thunderbolt power delivery specification is wrongly implemented by all SSD manufacturers.

Hi, I have a Studio Ultra, and 4 Acasis Thunderbolt 4/USB 4 enclosures. My Nvme’s are 2 Samsung 980 Pro and 2 Samsung 990 pro. Everything running their latest firmwares. Always when I connect the latest external disk is “negotiated” as USB 3.1 instead Thunderbolt (Pcie). It doesn’t matter which one I connect the latest. Always happens. I tried different combinations with drives, enclosures, cables,… always same bad end.

Something that scares me is that when connecting them to my MacBook Pro 14” (only 3 Thunderbolt 4 ports) I get same behavior. Latest Thunderbolt (3rd) drive is down to 10gbps instead 40gbps.

I said that scares me because the investment on a MacStudio Ultra is enormous plus the MacBook Pro 14”. This could be a firmware issue or something really ugly from Apple. They can not announce a Mac with up to 6 Thunderbolt 4 independent busses that only can handle 3 at top speed. I really can have a word for this.

My guess is that we have two options. This can be probably fixed with a firmware update, or in the bad case, no posible solution due a power issue (motherboard).

any advance?

regards

Same problem.

If you go into disk utilities you can watch it only allow one external drive run PCI-Express…

The rest default to USB.

Drives:

Two Scandisk Pros (1TB&2TB) and one Samsung 990 in a Orico M234C3 enclosure.

Note:

If you don’t plug the Samsung 990 in first, it never finds it at all…

the drive that gets plugged in first gets PCI-Express assigned and read writes at the proper speed, 2k+, the remaining never go above 900.

not good :(

same problem here. I have an ACASIS TBU401 enclosure, and it only shows thunderbolt/usb4 at 40Gbps when it's plugged in first (every time after restarts).

The ACASIS support told me that during their testing, only the first 2 plugged in devices will be allocated to Thunderbolt. Apparently it's an Apple issue

Same problem.

If you go into disk utilities you can watch it only allow one external drive run PCI-Express…

The rest default to USB.

Drives:

Two Scandisk Pros (1TB&2TB) and one Samsung 990 in a Orico M234C3 enclosure.

Note:

If you don’t plug the Samsung 990 in first, it never finds it at all…

the drive that gets plugged in first gets PCI-Express assigned and read writes at the proper speed, 2k+, the remaining never go above 900.

not good :(

I contacted the OWC support and they guaranteed me that the OWC Envoy Pro FX power draw is according to the Thunderbolt protocole specification. Thus the issue is very likely on Apple's side.

I have this EXACT same issue. I have a Mac Studio M2 Ultra and I'm currently running three Samsung 2TB 980 Pro NVME via Acasis external enclosures and the max you can run at full speed of around 2800/mbs read/white is three drives. I recently purchased a 4TB NVME via the same Acasis enclosure and it slows down to 500-800/mbs read/white when i plug in this 4th drive. I feel scammed by Apple because their wording says 6 Thunderbolt 4 ports but only 3 of them work at full speed at a time. I also purchased two OWC thunderbolt 4 hubs that are basically worthless because nothing after 3 drives runs at full speed.

Apple, if you're reading this, I want an explanation!!!!

Same problem.

If you go into disk utilities you can watch it only allow one external drive run PCI-Express…

The rest default to USB.

Drives:

Two Scandisk Pros (1TB&2TB) and one Samsung 990 in a Orico M234C3 enclosure.

Note:

If you don’t plug the Samsung 990 in first, it never finds it at all…

the drive that gets plugged in first gets PCI-Express assigned and read writes at the proper speed, 2k+, the remaining never go above 900.

not good :(

Same issue here. The tb3/usb4 storage device connects to the last available tb port on M1 Max Studio always shown as USB instead of bus/PCI-E device, regardless of disk+enclosure and port choices. The bandwidth degrades into 10Gbs so it seems instead of 40.

I have the standard Mac Studio, I have 3 different enclosures and have tried 10 different cables. I can only connect external storage to USB 2.0 or the storage hangs forever in finder. I've tried different file systems and repairs and formatting, it's always the same. It works perfectly on my Macbook Pro M2, but not the Mac Studio.

Sounds like there's a real issue here with power delivery or similar, in the system info I see that the port is only supplied the amount of power it needs exactly (500mah) which is almost too little, so when I send a lot of files att the same time, it hangs - even on USB 2.0.

Tried bringing it to an Apple shop and they just said there's no issue and will not go on warranty, so had to pay 500€ just for their time to look at it not working..

Same problem here, i have an mac studio max and bought 3 Acasis TBU401 enclosure with 3 4tb ssd 990 pro from samsung and i can only use 2 of them. doesn't matter which port, it's just the first 2 i use that work. I got a CalDigit Thunderbolt 4 Element Hub but did not try it yet. Anyway, it's very frustrating to pay another 300 euro for something that should have been provided by my very expensive mac studio!!! Please fix this

Yes I suspect the same thing. I just ordered all brand new Thunderbolt 4 cables from Apple and this did not resolve my issue. I'm going to be contacting Apple support and bring my Mac Studio M2 Ultra in for an evaluation. I want to get to the bottom of this issue.

Did you ever find a solution? I experienced the same thing and need a powered thunderbolt dock to get a third NVME drive in an Acasis tb405 enclosure.

I have exactly the same problem. When I connect my third acasis enclosure with wd 770 NVMe, the macmini M2 Pro recognise like usb 3.1 and not thunderbolt 4 connection…with low speeds 900mb/s

How can I measure the actual bandwidth?