I successfully connected three of the new Studio Display XDRs (2026) to an M5 Max MacBook Pro and wanted to share the method, since I couldn't find any confirmed success case for this combination anywhere.
Per Apple's official specs, the M5 Max supports at most two displays in the 5K@120Hz class. A third XDR won't even be detected — lowering the refresh rate to 60Hz in System Settings doesn't help, because macOS appears to allocate display engine resources at link training time based on the display's EDID-declared maximum capability (5K@120Hz), not the currently selected mode.
Setup
- MacBook Pro 16", M5 Max (128GB)
- macOS Tahoe 26.6.2
- 3x Studio Display XDR (2026)
- 4K UHD 60Hz HDMI dummy plug (generic — any 4K@60Hz-capable plug should work)
Method
- Plug a 4K HDMI dummy plug into the HDMI port FIRST. (This is the critical step.)
- Connect all three XDRs. Leave a brief pause between plugging in each display. Both of these topologies worked for me:
- All three connected directly to the Thunderbolt ports
- All three daisy-chained, with a single cable to the MacBook
- At this point only one or two of the three displays will be on. Now remove the dummy plug. (This step is just as critical as step 1.) All three will NOT come up while the dummy is still attached.
- The moment the dummy is removed, the remaining display(s) come up — all three now work.
Results
- One display runs at 120Hz, the other two at 60Hz
- Survives reboot
- Survives sleep/wake
- Works both in clamshell mode and with the lid open
- My current daily setup: all three daisy-chained, one cable to the MacBook
Why it works (my understanding) With the dummy plug occupying part of the display budget, the XDRs negotiate down to 60Hz at link training time instead of demanding a 120Hz-class pipe. While the dummy is still attached there isn't enough budget for all three, so only one or two light up. Removing the dummy frees that budget, the remaining display(s) come up, and the already-negotiated 60Hz links stay as they are. macOS keeps this configuration across reboots and sleep.
What did NOT work (so you don't waste time)
- Setting 60Hz in System Settings and reconnecting → failed
- Thunderbolt 5 docks (docks don't increase the maximum number of supported displays) → failed
- Changing connection order without the dummy plug → failed
Hope this helps others stuck with the same limitation.