Can an M2 Pro Mac Mini drive the new Studio Display XDR @ 120Hz?

Grant Bennet-Alder wrote:

In addition, on Thunderbolt-3 or -4 Macs, that display is driven by TWO display-generators, so it counts as TWO of your total number of External displays.

There are Intel-based Macs where using a 5K display reduces the total number of supported displays, but I don't believe that there are any Apple Silicon (M-series) Macs that impose such a tradeoff. (I have seen tradeoffs when it comes to resolutions above 6K or refresh rates over 60 Hz.)

Mac mini (2023) - Tech Specs – Apple Support says this about the M2 Pro Mac mini.

----------

Apple M2 Pro chip

Simultaneously supports up to three displays:

• Up to three displays: Two displays with up to 6K resolution at 60Hz over Thunderbolt and one display with up to 4K resolution at 60Hz over HDMI
• Up to two displays: One display with up to 6K resolution at 60Hz over Thunderbolt and one display with up to 4K resolution at 144Hz over HDMI
• One display with up to 8K resolution at 60Hz or 4K resolution at 240Hz over HDMI

----------

However, I believe that the original 27" Apple Studio Display consumed both of the DisplayPort sessions available within a single Thunderbolt 3 or 4 connection. So while a M2 Pro Mac mini can drive two 27" Studio Displays, you would need to drive them from different Thunderbolt ports.

<< Does that mean the M2 Pro and M2 Max are capable of 120Hz on Thunderbolt 4? >>

No. Their ThunderBolt-3 or -4 busses are limited to "slower" data rates up to 40 G bit/sec maximum, which limits every model of Studio Display XDR to 60 Hz maximum at HDR 10 bits/color.

In addition, on Thunderbolt-3 or -4 Macs, that display is driven by TWO display-generators, so it counts as TWO of your total number of External displays.

When the newer model XDR display is connected on a Thunderbolt -3 or -4 bus out of the Mac, there is very little bandwidth left for other devices. Both the ThunderBolt hub and the USB hub can be used, but Not for daisy-chaining another display or supporting a high-speed device like a disk drive at its rated speed.

Keyboards? sure.

USB Thumb Drive when needed? no problem.

--------

The big boost in data rates happens when every item -- the Mac port, the Thunderbolt-5 cable, AND the external device -- are all rated for Thunderbolt-5, and not otherwise. Thunderbolt-5 uses a different advanced signaling method, and every device must be capable of using that advanced signaling method, or none can.

den.thed wrote:

According to the 2023 Mac mini Spec's, only the M2 Pro supports refresh rates above 60Hz.

see "Display Support" at > Mac mini (2023) - Tech Specs

and > Connect a display to Mac mini

And that is on the HDMI port – which is useless for driving the new 27" Apple Studio Display.

According to the 2023 Mac mini Spec's, only the M2 Pro supports refresh rates above 60Hz.

see "Display Support" at > Mac mini (2023) - Tech Specs

and > Connect a display to Mac mini

Since you brought it up, this is the quote I left out for simplicity:

XDR display

The 6K Apple Pro Display XDR, which macOS allows to connect using two HBR3 connections to a Mac, doesn't support Display Stream Compression (DSC). That would be 51.84 Gbit/s, impossible for Thunderbolt 3, but it works because the two 3008×3384 10bpc 60 Hz 648.91 MHz signals of the XDR display only require 38.9 Gbit/s total and Thunderbolt does not transmit the DisplayPort stuffing symbols used to fill the HBR3 bandwidth.

https://en.wikipedia.org/wiki/Thunderbolt_(interface)

aside to Servant of Cats:

Before I had time to cut and paste anything else onto my computer clipboard, a user complained [I think for the first time] that they could not connect TWO XDR displays to a Mac Book Pro with PRO Processor M3 or M4:

https://discussions.apple.com/thread/256262701?answerId=261869890022&sortBy=rank

maybe you can see something there that I did not, other than not enough display-generators.

Grant Bennet-Alder wrote:

aside to Servant of Cats:

Before I had time to cut and paste anything else onto my computer clipboard, a user complained [I think for the first time] that they could not connect TWO XDR displays to a Mac Book Pro with PRO Processor M3 or M4:

https://discussions.apple.com/thread/256262701?answerId=261869890022&sortBy=rank

maybe you can see something there that I did not, other than not enough display-generators.

The model identifier on the M3 Pro MBP seems to indicate that it is the 16-inch model.

MacBook Pro (16-inch, Nov 2023) - Tech Specs – Apple Support

According to its specifications, it can drive "Up to two external displays with up to 6K resolution at 60Hz over Thunderbolt." While the OP's attempts to daisy-chain two Pro Display XDRs from one Thunderbolt port were doomed to failure, it should have been possible to drive two Pro Display XDRs from separate ports.

Servant of Cats wrote:

Grant Bennet-Alder wrote:

In addition, on Thunderbolt-3 or -4 Macs, that display is driven by TWO display-generators, so it counts as TWO of your total number of External displays.

There are Intel-based Macs where using a 5K display reduces the total number of supported displays, but I don't believe that there are any Apple Silicon (M-series) Macs that impose such a tradeoff. (I have seen tradeoffs when it comes to resolutions above 6K or refresh rates over 60 Hz.)

I have to amend that statement. The Technical Specifications for the M5-series MacBook Airs and Pros now say that you can connect displays with a resolution of 5K and a refresh rate of 120 Hz.

This comes at a reduction in the total number of external displays.

• For notebooks with plain M5 chips and Thunderbolt ports, that can normally drive up to two displays, driving a 5K display at 120 Hz limits you to a single external display.
• You need a MacBook Pro with a M5 Pro or M5 Max chip, and Thunderbolt 5 ports, to be able to drive two such displays. And once again, it cuts down the number of supported external displays, from 3 or 4, to 2.

This lends credence to your hypothesis that running the Studio Display XDR at its full resolution and refresh rate requires using TWO display generators. And the follow-up hypothesis that when the Mac sees the capability of the display, it may be reserving those TWO display generators even if it subsequently turns out that you run the display at a 60 Hz refresh rate.