How to connect old Apple Cinema Display 27"? Daisy chain to Studio Display?

[danqi]

I would like to keep using my old Mini Displayport 27" Apple Cinema Display (from ca. 2011) as a secondary monitor on the Mac Studio.

From my initial research it seems like HDMI to Mini Displayport adapters are problematic. I would also like to avoid using one of the Thunderbolt 4 ports as I need those for SSDs and the Studio Display.

Can I daisy chain the Cinema Display to one of the Studio Display's USB-C ports via an USB-C to Mini Displayport adapter?

 

[velocityg4]

I would like to keep using my old Mini Displayport 27" Apple Cinema Display (from ca. 2011) as a secondary monitor on the Mac Studio.

From my initial research it seems like HDMI to Mini Displayport adapters are problematic. I would also like to avoid using one of the Thunderbolt 4 ports as I need those for SSDs and the Studio Display.

Can I daisy chain the Cinema Display to one of the Studio Display's USB-C ports via an USB-C to Mini Displayport adapter?

The USB-C ports only do USB. Those adapters require a USB C port which is capable of ALT mode for DP.

Unless it is a DisplayLink adapter. Which will do graphics over USB but it suffers from a little latency.

 

[danqi]

Thanks! Do you know if the USB C ports on the front of the Mac Studio Max would work? It's not really elegant, but I see no other option...

 

[velocityg4]

Thanks! Do you know if the USB C ports on the front of the Mac Studio Max would work? It's not really elegant, but I see no other option...

The Mac Studio has four Thunderbolt ports. Why not use one for the Studio display and one for the other monitor? You can use a dock to split up the Thunderbolt port if needed. So you have Thunderbolt data available and DP from a separate port.

I don't think the USB 3.1 Gen 2 ports do DP alt mode either.

 

[danqi]

The Mac Studio has four Thunderbolt ports. Why not use one for the Studio display and one for the other monitor? You can use a dock to split up the Thunderbolt port if needed. So you have Thunderbolt data available and DP from a separate port.

I don't think the USB 3.1 Gen 2 ports do DP alt mode either.

The problem is that I am using all those Thunderbolt ports:

Studio Display
Fast scratch disk (nvme SSD)
Fast media work disk (nvme SSD)
SATA HDD & SSD enclosure

If I were to combine any of those using a dock/hub I would loose speed. Unless I could combine the two displays of course, but I doubt that that is possible.

 

[velocityg4]

I'd expect there's enough bandwidth on a Thunderbolt port for a Cinema display with the SATA HDD & SSD.

 

[danqi]

I'd expect there's enough bandwidth on a Thunderbolt port for a Cinema display with the SATA HDD & SSD.

So you're saying buy a hub that basically splits one Thunderbolt port into two and attach the HDD/SSD enclosure to one of those ports and the Cinema Display to the other (using an adapter)?

I had not considered that. I guess the Cinema Display shouldn't take away too much bandwith...

But I can't seem to find any simple Thunderbolt hubs that turn 1 port into 2. It's all just bigger docks.

 

[velocityg4]

So you're saying buy a hub that basically splits one Thunderbolt port into two and attach the HDD/SSD enclosure to one of those ports and the Cinema Display to the other (using an adapter)?

I had not considered that. I guess the Cinema Display shouldn't take away too much bandwith...

But I can't seem to find any simple Thunderbolt hubs that turn 1 port into 2. It's all just bigger docks.

Yes, this OWC dock will allow three Thunderbolt 3/4, USB 4 devices. Along with three USB 3.1 Gen 2 Type A ports. The Thunderbolt ports allow one 5k or two 4K displays.

OWC Docks, Hubs, Docking Stations, and More

Find the perfect dock for any Thunderbolt or USB-C workflow. We also offer video display adapters, drive docks, laptop docking stations and video adapters.

www.owcdigital.com

There's also the Caldigit TS4.

Thunderbolt 4 Dock | TS4 | CalDigit – CalDigit

www.caldigit.com

I'm sure there's a few other Thunderbolt 4 docks. A lot more Thunderbolt 3 docks.

I wouldn't be surprised if one or more comes out soon to match the Mac Studio and sit underneath it. There must be one or more for the Mac Mini. But I don't know how the length and width compares to the Studio and don't feel like checking.

 

[danqi]

Yeah, good point, I guess the Mac Studio will cause a lot of peripherals to appear over the next few months. Might be best to keep it simple for now and see what comes up...

 

[anson42]

Pretty sure the front USB-C ports would work for this if you don't mind an adapter sticking out the front. I have an old Cinema Display, too, and I have a USB-C to Mini-DisplayPort adapter plugged into the back of a M1 Mac mini Thunderbolt port. With this adapter, the port acts as a USB-C port with alt mode support. I would be shocked if the front ports of the Max Studio couldn't do this, aesthetics aside.

 

[OSB]

Why not consider daisy chaining some of the drives? The TB4 bus won't be saturated by any of those drives, and anyhow you could always keep the NVME scratch drives first in the chain and hang your bulk storage drives off the backs of those...

 

[joevt]

If you just want more Thunderbolt 4 ports, then get a Thunderbolt hub from OWC or Sonnet or whoever. The CalDigit Element Hub is about the same size as those but has 3 additional type-A ports.
You can connect both displays to the same Thunderbolt hub if the Apple Studio Display is connecting using DSC single tiled mode instead of non-DSC dual tiled mode.

Are any of your drives non-Thunderbolt? If so, then one or two of them can be connected to the USB hub of the Apple Studio Display.

Thunderbolt is 40 Gbps.
The Apple Studio Display uses 11.3 Gbps with single tile DSC connection and 29 Gbps for dual tile connection.
The old Cinema Display uses 7.3 Gbps.

 

[danqi]

Pretty sure the front USB-C ports would work for this if you don't mind an adapter sticking out the front. I have an old Cinema Display, too, and I have a USB-C to Mini-DisplayPort adapter plugged into the back of a M1 Mac mini Thunderbolt port. With this adapter, the port acts as a USB-C port with alt mode support. I would be shocked if the front ports of the Max Studio couldn't do this, aesthetics aside.

I think I am just going to try this once I have everything. It's not ideal from an aesthetics point of view, but functionality trumps aesthetics.

Why not consider daisy chaining some of the drives? The TB4 bus won't be saturated by any of those drives, and anyhow you could always keep the NVME scratch drives first in the chain and hang your bulk storage drives off the backs of those...

I actually do think that the NVME drives should be able to max out the TB4 ports, unless I am misunderstanding something. But I did not know the daisy chaining order plays a role. So the first drive always gets priority?

If you just want more Thunderbolt 4 ports, then get a Thunderbolt hub from OWC or Sonnet or whoever. The CalDigit Element Hub is about the same size as those but has 3 additional type-A ports.
You can connect both displays to the same Thunderbolt hub if the Apple Studio Display is connecting using DSC single tiled mode instead of non-DSC dual tiled mode.

Are any of your drives non-Thunderbolt? If so, then one or two of them can be connected to the USB hub of the Apple Studio Display.

Thunderbolt is 40 Gbps.
The Apple Studio Display uses 11.3 Gbps with single tile DSC connection and 29 Gbps for dual tile connection.
The old Cinema Display uses 7.3 Gbps.

I just noticed something I had completely overlooked for some reason (planning stuff like this can get very confusing). Instead of getting a dock/hub couldn't I just connect my slowest drive to one of the ports of the Studio Display? I should still be getting about 11 Gbps from that, which is USB 3.2 speed, right?

 

[anson42]

I just noticed something I had completely overlooked for some reason (planning stuff like this can get very confusing). Instead of getting a dock/hub couldn't I just connect my slowest drive to one of the ports of the Studio Display? I should still be getting about 11 Gbps from that, which is USB 3.2 speed, right?

Oh, I totally misread that you are planning a Studio Display, too. In that case, the SD has three USB-C ports and the one Thunderbolt. You can definitely plug in the slower HDD storage into one of those USB-C ports. There's no mention of display port possibilities from those USB-C ports but if you want to preserve a TB port on the back of the Studio I would also try chaining the Cinema Display from a Studio Display USB-C port as well. But it does seem like your port count issue now addressed.

 

[danqi]

if you want to preserve a TB port on the back of the Studio I would also try chaining the Cinema Display from a Studio Display USB-C port as well. But it does seem like your port count issue now addressed.

Yeah, that was my original idea and I thought that might be my only sensible option. But now that I know I'll have several options I will just order everything and then try out some variations.

 

[OSB]

I actually do think that the NVME drives should be able to max out the TB4 ports, unless I am misunderstanding something. But I did not know the daisy chaining order plays a role. So the first drive always gets priority?

I believe the rule of thumb is that your fastest device should always be first in any chain, you should chain all TB4 devices before all TB3 devices before all TB2 before all USB, and your monitor should always be the last TB device.

TB4 has a (theoretical) peak bandwidth of 40Gbs, or 5000MB/sec. What speeds are you actually seeing from your SSDs? I haven't seen any external TB NVME enclosures do materially better than ~3000MB/s - but it's been a year since I last looked hard into it. If that's the range you're seeing, that still leaves plenty of bandwidth for bulk storage to live behind.

 

[danqi]

I believe the rule of thumb is that your fastest device should always be first in any chain, you should chain all TB4 devices before all TB3 devices before all TB2 before all USB, and your monitor should always be the last TB device.

TB4 has a (theoretical) peak bandwidth of 40Gbs, or 5000MB/sec. What speeds are you actually seeing from your SSDs? I haven't seen any external TB NVME enclosures do materially better than ~3000MB/s - but it's been a year since I last looked hard into it. If that's the range you're seeing, that still leaves plenty of bandwidth for bulk storage to live behind.

I don't actually own the fast (nvme) SSDs yet. I've just seen information that they should be able to max out a TB4 connection during my research, but maybe I need to double check that. Or maybe I just order everything and try it out...

Do you see a problem with attaching a USB 3.2 SATA 4-bay enclosure (with 3 SATA SSDs and 1 SATA HDD) to one of the Studio Display's USB-C ports?

 

[OSB]

I don't actually own the fast (nvme) SSDs yet. I've just seen information that they should be able to max out a TB4 connection during my research, but maybe I need to double check that. Or maybe I just order everything and try it out...

Do you see a problem with attaching a USB 3.2 SATA 4-bay enclosure (with 3 SATA SSDs and 1 SATA HDD) to one of the Studio Display's USB-C ports?

I believe the bandwidth requirement for 5K/60 is about 22Gbs, which (even accounting for non-optimal results and some bandwidth for the camera and audio) should leave you with something in the area of 2000MB/sec for the SATA USB array... I would think would be plenty unless you're doing something crazy like running the SSDs in a 3x RAID0.

 

[joevt]

22Gbps

For 8bpc. 10bpc requires 29Gbps.

 

[danqi]

For 8bpc. 10bpc requires 29Gbps.

So that should still leave about 11Gbps which is more than the full capacity of USB 3.2 Gen 2, right?

 

[joevt]

So that should still leave about 11Gbps which is more than the full capacity of USB 3.2 Gen 2, right?

Yup but you might see some slightly lower performance anyway since its very close? I should test this with my Dell UP2715K and a Thunderbolt 4 hub...

 

[OSB]

I wouldn't be surprised if the array was a little slower hanging off the monitor compared to its own dedicated bus. If it's just bulk storage though, it shouldn't make *that* much of a difference to one's day-to-day. YMMV.

 

[joevt]

I wouldn't be surprised if the array was a little slower hanging off the monitor compared to its own dedicated bus. If it's just bulk storage though, it shouldn't make *that* much of a difference to one's day-to-day. YMMV.

I did a test in Monterey 12.3 using an HFS+ formatted partition (speed of FAT partition is 85% of HFS+).
Below are AmorphousDiskMark read/write MB/s results:
- 1060/1058: Mac mini 2018
- 1017/999: CalDigit Element Hub
- 1015/754: CalDigit Element Hub with Dell UP2715K connected with two USB-C to Dual DisplayPort adapters to the same hub to so that the hub simulates an Apple Studio Display assuming the Apple Display is not using a secondary USB hub.

The Dell uses 483.25MHz for each tile while the Studio Display uses 482.4MHz so they are close enough.

You see that the read speed is slightly lower and the write speed is reduced to 75% because of the bandwidth used by the display. Now, if your drive is not 1000 MB/s then you probably won't see a reduction like this. And of course these are sequential read/write tests. Random read/write will be much lower so they may be affected by the display bandwidth less.

 

[danqi]

I did a test in Monterey 12.3 using an HFS+ formatted partition (speed of FAT partition is 85% of HFS+).
Below are AmorphousDiskMark read/write MB/s results:
- 1060/1058: Mac mini 2018
- 1017/999: CalDigit Element Hub
- 1015/754: CalDigit Element Hub with Dell UP2715K connected with two USB-C to Dual DisplayPort adapters to the same hub to so that the hub simulates an Apple Studio Display assuming the Apple Display is not using a secondary USB hub.

The Dell uses 483.25MHz for each tile while the Studio Display uses 482.4MHz so they are close enough.

You see that the read speed is slightly lower and the write speed is reduced to 75% because of the bandwidth used by the display. Now, if your drive is not 1000 MB/s then you probably won't see a reduction like this. And of course these are sequential read/write tests. Random read/write will be much lower so they may be affected by the display bandwidth less.

Awesome and informative, thanks for doing the test!