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Note that the 28 CPU core M3 Ultra can still be configured with 256GB of RAM, which means it has the full 8 controllers and SDRAMs (at 32GB each.)
Interesting, I just assumed the base M3 Ultra must have been just two binned M3 Max stitched so it would also carry over the same limits. Turns out there’s more to it.
 
I am having lots of issues with monitors - been using a Studio Display and a LD 32 4K monitor and a Huion Kamvas Pro 24 Pen display I have used these for years connected to a MacPro 2019. I am unable to get all of these working with the Mac Studio M4 Max. I can get both the studio Display and LG displays working fine. Last week with a combination of Huion and LG on HDMI I got all three working. Then I upgraded to 15.4 and the Huion no longer registers in Displays. Still works fine when plugged into a MacBook Pro so its definitely the Mac Studio. Reading this thread makes me wonder if I need a hub as its a power drain issue any thoughts/ I already have 3 storage units connected via am OWC TB Hub as well which works fine.

Today (04/02/2025)I received a different answer from Apple support on this issue. They have recognised an issue, which they believe is software and are now working on a fix. This seemed like progress and should help most issues above as well.
 
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Unbelievable that the Apple monks still did not fix this glaring TB bug in even the latest Mac Studio M variant. They are clearly not producing for Pro's anymore.


It’s a well known issue for Apple desktops. Despite Apple advertising them as Thunderbolt 4/5, they don’t always meet the power requirements of supplying 15W to external unpowered devices. I have a M4 Mac Mini and a M4 Max Mac Studio, and they can only power 2 external Thunderbolt drives. All 3 of my drives are Thunderbolt only (like your Acasis Air model). Some Acasis enclosures have a USB fall-back option and will connect at USB 3.1 Gen 2 speeds when there is not enough power. I suppose the Lacie drive in the Apple store was a 3.1 Gen 2 device, which is why it connected.

More information in this thread here ->
'M4 Mac Mini - External Thunderbolt Drives Limitation'
https://forums.macrumors.com/threads/m4-mac-mini-external-thunderbolt-drives-limitation.2445812/
 
Unbelievable that the Apple monks still did not fix this glaring TB bug in even the latest Mac Studio M variant. They are clearly not producing for Pro's anymore.
The issue with connected displays is a Software issue. Apple has confirmed this and are working on a fix. My Display pen Provider Huoin was really helpful and provided a potential fix, which is to delete plist files relayed to displays. I am waiting for the fix as I don't wish to make the situation worse and the directory structure they described doesn't match the Library structure. please note that all my TB connected devices work fine aside fro, displays
 
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The issue with connected displays is a Software issue. Apple has confirmed this and are working on a fix. My Display pen Provider Huoin was really helpful and provided a potential fix, which is to delete plist files relayed to displays. I am waiting for the fix as I don't wish to make the situation worse and the directory structure they described doesn't match the Library structure. please note that all my TB connected devices work fine aside fro, displays
My confidence level in them fixing anything is low to none.

Have you seen the 5k display thread? They have known about this since the M4 release and we still do not have a fix.

Your issue with one monitor not connecting sounds like a possible bandwidth issue. Have you tried using better display to force your other monitors to connect using 8 bit instead of 10bit?
 
Thanks to everyone for their replies & info.
I've decided to keep the Studio & just deal with the Thunderbolt issues.

Today, I ordered the OWC Thunderbolt 5 hub off Amazon, to hopefully allow me to connect all 3 Acasis Thunderbolt enclosures/2TB drives along with my 2nd Dell monitor.

I'll reply back once I get the hub & let everyone know how it goes.

Experienced a strange issue just a few minutes ago for the 2nd time today: I installed Sequoia onto the TB501 Pro Thunderbolt 5 with 2TB WD SN850X SSD earlier today & have been booting off of it. I just powered up to reply here & all of a sudden, my monitor/display lost video signal. This is the monitor that's plugged into the HDMI port. The other monitor is currently unplugged as I wait for the OWC TB 5 hub. I don't think this was a video issue though. I get the sneaky suspicion that this was related to a connection loss with the TB501 Pro running Sequoia. So I booted off the Studio's internal SSD to post this reply.

Ugh, Apple. If only your internal storage was affordable, I'd have at least 4TB SSD built in.

Another thought: If the OWC hub runs well, maybe I'll RAID 0 the TBU405 Air drives. Has anyone here tried it with external TB drives? Results?
I have tried TWO OWC TB5 hubs to my Mac Studio. Nothing works. And the system report does not show anything connected
 
so its definitely the Mac Studio.
glad to read i´m not alone. sorry for you ofcoarse.

i run right now 3 different display threads. figure that


ok, at least this helps to understand that i have to be very cautious and flexibel vs. what i´m doing and that i´m on the right track ( spent so far lots of money allready for cables and hubs and converters etc.)


One would have guessed that the studio operates display flawless, and at least better than the cheap M4mini base. But the contrary is the case. I also have the small mini.....i just swichted
 
I have tried TWO OWC TB5 hubs to my Mac Studio. Nothing works. And the system report does not show anything connected
Interesting, I can use both a OWC and a Akitio Pro dock, both TB3 and are powered, to bypass the issue of the Studio not providing enough bus power.

I think OWC has only released one TB5 hub and it is definitely DC powered? I wonder what has changed.
 
Thanks to everyone for their replies & info.
I've decided to keep the Studio & just deal with the Thunderbolt issues.

Today, I ordered the OWC Thunderbolt 5 hub off Amazon, to hopefully allow me to connect all 3 Acasis Thunderbolt enclosures/2TB drives along with my 2nd Dell monitor.

I'll reply back once I get the hub & let everyone know how it goes.

Experienced a strange issue just a few minutes ago for the 2nd time today: I installed Sequoia onto the TB501 Pro Thunderbolt 5 with 2TB WD SN850X SSD earlier today & have been booting off of it. I just powered up to reply here & all of a sudden, my monitor/display lost video signal. This is the monitor that's plugged into the HDMI port. The other monitor is currently unplugged as I wait for the OWC TB 5 hub. I don't think this was a video issue though. I get the sneaky suspicion that this was related to a connection loss with the TB501 Pro running Sequoia. So I booted off the Studio's internal SSD to post this reply.

Ugh, Apple. If only your internal storage was affordable, I'd have at least 4TB SSD built in.

Another thought: If the OWC hub runs well, maybe I'll RAID 0 the TBU405 Air drives. Has anyone here tried it with external TB drives? Results?
I tried the OWC TB5. Never got it to work with my 2025 Mac Studio. Returned in. Now using the
iVANKY Intel Certified Thunderbolt 5 Dock . Connects everything fine but now having an issue with external drives disconnecting when system goes to sleep. And the setting for powering down disks is set correctly
 
I tried the OWC TB5. Never got it to work with my 2025 Mac Studio. Returned in. Now using the
iVANKY Intel Certified Thunderbolt 5 Dock . Connects everything fine but now having an issue with external drives disconnecting when system goes to sleep. And the setting for powering down disks is set correctly
Just out of curiosity, what didn't work about the OWC TB5?
 
I have 3 OWC Thunderblade V4 drives all connected to a single OWC TB Hub, and I have had no issues when connecting with a single TB cable from the Hub to my M4 Max Mac Studio.....
So the above uses one of my Studio TB ports, ASD uses another of course, and I have had 2 OWC 1M2 drives connected to the final 2 ports. That's the max I've ever gone, and likely to go at any one time, and its been OK for me........

Bear in mind I always disconnect my drives once I'm done using them for that session - so rarely place my computer to sleep etc with any drives connected......
 
I use the new Acasis Thunderbolt 5 SSD Drive and have problem whene use 2 other Acasis Thunderbolt 4 Drive on my Mac Studio M4 Max. I have 3 Acasis Thunderbolt Drive (TBU405 Air, TB501Pro and TBU405 Pro) and whene use all 3 the Thunderbolt 5 Drive not work. Only whene use 2 Drive its work. Is there any Incompatibility and how can fix it? In all 3 Drive i use KINGSTON Fury SSD with latest Firmware.
 
I use the new Acasis Thunderbolt 5 SSD Drive and have problem whene use 2 other Acasis Thunderbolt 4 Drive on my Mac Studio M4 Max. I have 3 Acasis Thunderbolt Drive (TBU405 Air, TB501Pro and TBU405 Pro) and whene use all 3 the Thunderbolt 5 Drive not work. Only whene use 2 Drive its work. Is there any Incompatibility and how can fix it? In all 3 Drive i use KINGSTON Fury SSD with latest Firmware.
All Macs have problems mounting bus powered external SSDs once you reach the 3rd one connected. It is an undocumented, but frequently discovered and discussed limit even on this forum. You may want to search and read up on them as the scenarios and solutions have many variables.

But I can give you a short answer for your scenario: you need to at least move one of the drives to an independently powered source, such as a powered Thunderbolt dock.
 
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rarely place my computer to sleep etc with any drives connected......
You let your computer go to sleep?
/s

While my displays turn themselves off, my Studio itself is always running, but I prefer it, so things like email filters and such continue running.
 
All Macs have problems mounting bus powered external SSDs once you reach the 3rd one connected. It is an undocumented, but frequently discovered and discussed limit even on this forum. You may want to search and read up on them as the scenarios and solutions have many variables.

But I can give you a short answer for your scenario: you need to at least move one of the drives to an independently powered source, such as a powered Thunderbolt dock.

Why all Macs have such problems?
 
You let your computer go to sleep?
/s

While my displays turn themselves off, my Studio itself is always running, but I prefer it, so things like email filters and such continue running.

I only really use an external drive when editing. When I finish I unplug the drive and place the computer to sleep.
I do the same when I just need to check emails or do other stuff - as soon as I finish I close all running programs, and place the computer to sleep before walking away......
 
Why all Macs have such problems?
You have to ask Apple. If this only happens on MacBooks then we can at least conjecture it have to do with reserving power for the rest of the system, but this happening also on minis and Studios.

Also I should say "all Apple Silicon Macs" that exhibit this issue, because I don't remember anyone reporting this during the TB3 Intel Macs era.
 
@Chancha re: ‘All Macs have problems mounting bus powered external SSDs once you reach the 3rd one connected.’
“I don't remember anyone reporting this during the TB3 Intel Macs era.”


During the TB3 era everything was certified by Intel, especially power consumption limits.

Bus powered enclosures were the exception, because of Intel’s scrutiny.

PCIe 3 was the fastest available, and larger capacities were extremely rare.
Both put limits on excess power consumption.

And most importantly, desktop Macs had logic board areas more than x4, which allowed power traces on the PCB to be the size that was needed to supply ample power to all sockets.

Compounding the AS miniaturised logic board problem is that, in their desktops, Apple has now fitted tiny trace flexible ribbon cables to connect all their vertical Thunderbolt 4/5 ports…

So the ‘problem’ is what it it is, because Apple does what it does,
And non-Intel TBn enclosure manufacturers do what they do… ;)
 
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Wondering if we can do a group petition to Apple to correct this issue?
This will weigh in on my future purchase decisions...
 
@Chancha re: ‘All Macs have problems mounting bus powered external SSDs once you reach the 3rd one connected.’
“I don't remember anyone reporting this during the TB3 Intel Macs era.”

During the TB3 era everything was certified by Intel, especially power consumption limits.

Bus powered enclosures were the exception, because of Intel’s scrutiny.

PCIe 3 was the fastest available, and larger capacities were extremely rare.
Both put limits on excess power consumption.

And most importantly, desktop Macs had logic board areas more than x4, which allowed power traces on the PCB to be the size that was needed to supply ample power to all sockets.

Compounding the AS miniaturised logic board problem is that, in their desktops, Apple has now fitted tiny trace flexible ribbon cables to connect all their vertical Thunderbolt 4/5 ports…

So the ‘problem’ is what it it is, because Apple does what it does,
And non-Intel TBn enclosure manufacturers do what they do… ;-(
Thank you for the explanation. I was puzzled on why this is happening for years and this makes perfect sense to me now.
 
God, I'm so glad I found this thread. I bought a tricked out Mac Studio M4 Max last March and I have had nothing but *problems* with the ports and external drives. I've been on multiple Apple Support calls and even been bumped up to a senior tech advisor, who basically pushed my issues until after Tahoe dropped--apparently MacOS 26 is supposed to be the bug fix for Sequoia. I haven't installed it yet as I'm waiting for the first dot release.

I have had the same issues, with incompatibility with Thunderbolt 2 devices, USB 3 drives, and USB-C connections. There seems to be a *SERIOUS* issue with power management in all the ports of both my Mac Studio and Apple Studio Display (That's even worse as the USB-C ports in the back are constantly fighting for power from the Thunderbolt 5 input, which has precedence, making the ports practically unusable). Every couple weeks my Studio will go to sleep and it's a dice toss if it doesn't corrupt my external SSD's to the point where they are unrecoverable and the drive needs to be reformatted and restored from a disc backup.

Long story short, I feel like I've been going crazy the last couple of months. I have rebooted and run disk utilities and bought hubs and new cables and on and on and on. At least 30% of the last seven months has been babying my Mac Studio and trying to get it to operate stably with external drives. I feel like I'm back on Windows 98 again. This is, without doubt, the worst Apple computer I have ever owned. I think I've bought seven in my life and none of them were as unremittingly unstable as this POS. If Apple would give me back my $6K+ I'd return this **** to the store within an hour. Like, no hesitation whatsoever.

So, that's where I'm at with my Mac Studio. This thread has made me feel less crazy and given me the idea of plugging all my drives into powered hubs to offset the issues with the Studio's built in ports. I'll give that a try. But I never thought I'd have issues with an Apple computer like I have with this Studio M4 Max. How the mighty have fallen.
 
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Very sad indeed, especially when the company boasts of billion dollars of resources, etc., blah, blah, blah...
 
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@evatar
Part of the problem is that there are two ends to a USB-C cable, and addressing incompatibilities with only the manufacturer of the device at one of the cable isn't going achieve a resolution with any shortcomings with the device at the other end of the cable...

Anyway, you've brought up the 'problem' with Apple in a very diligent way.
Which may or may not work, as Apple's historical (and widely known) modus operandi seems to be to tell the customer 'you must be holding it wrong'. :rolleyes:

The trouble is, part of the reason that Apple is the hugely successful company it has become is that it does it the way it does - saying 'No' to ninety-nine things before saying 'Yes' to the device it wishes to develop, manufacture and sell.
In huge quantities.

When Apple led the market into introducing USB with the original iMac, it was a replacement for ADB keyboard/mice connectivity. For external hard disk connectivity Apple continued to use SCSI, and developed FireWire.

And this continued, with no Apple development of USB beyond USB 2, until Thunderbolt came along in 2011 for high bandwidth or timing critical peripherals.
USB 3 was a secondary port from 2012 on.

Then in 2016 Apple made their intended roadmap clear, with the MBP and all future Macs going TB3+ on all main USB-C ports.

As I said earlier in the thread, since the the introduction of Thunderbolt, Apple and Intel have endeavoured to enforce absolute compatibility between the (certified) devices at both ends of the (TB3/4/5) cable.

If Apple's optimised hardware port design isn't 'compatible' with certain widely used (in the Windows or Linux world) USB 3.x devices, then Apple will probably tell you (politely) a variation of you're 'holding it wrong'. 😶

Don't use USB 3.x hubs, powered or not. USB is controlled by the computer's CPU, and is a protocol, like wi-fi, that doesn't have the highest priority, and can be interrupted if something else with a higher priority is happening.

Stick to TB3/4/5, which is a protocol that has higher priority via the PCIe bus.
Attach any USB 3.x storage devices to a TB3 dock, which has its own USB 3.x controller, and which provides all the necessary power.

TB4/5 docks or hubs still pass USB3.x port control back to the Macs controller, so problem USB 3.x devices can still be problematic.

And don't hang high bandwidth storage devices off the back of a monitor.
It will always prioritise the video data stream, that's its function.
And with 4K or larger monitors becoming more widespread, more of the connecting USB-C/TB3+ cable's bandwidth is needed for video data. And the longer cables used with monitors have problems retaining higher bandwidth - hardly any 2m+ cables (Apple excepted) can pass USB 3.2 Gen 2 (10Mbps) data as well as 5/6K video.
 
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evatar:
"MacOS 26 is supposed to be the bug fix for Sequoia. I haven't installed it yet as I'm waiting for the first dot release."

Why keep fighting with it?
I'd install 26.0.1 and be done with it.
 
evatar:
"MacOS 26 is supposed to be the bug fix for Sequoia. I haven't installed it yet as I'm waiting for the first dot release."

Why keep fighting with it?
I'd install 26.0.1 and be done with it.
I'm not fighting it. I'm waiting on a solid dot release. I work off a lot of professional A/V software and I cannot take more time right now if there's an issue with Tahoe or an incompatibility.

Besides, there's no guarantee it will solve *anything*. The Apple tech told me these issues have been a problem since the M2 (apparently, the M1 was a real winner).
 
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