Compatibility · Observed in September 2026
MacBook Pro M5 Pro and M5 Max: why your 5K monitor is stuck at 60 Hz
The same monitor, the same cable: 165 Hz in 10-bit 5K on a MacBook Air M5, but 60 Hz on a MacBook Pro M5 Pro or M5 Max. It is not the monitor. It is the way macOS 26 drives DisplayPort through Thunderbolt 5. Here is what we measured, and what it changes for you.
The finding, under our test conditions
We connected the same monitor with the same cable to several Macs. The result is clear:
- MacBook Air M5 — the monitor works normally at 5K at 165 Hz in 10-bit.
- MacBook Pro M5 Pro and M5 Max — the refresh rate falls back to 60 Hz, with no way to select anything better.
- Mac M4 and M5 on Thunderbolt 4 — no problem, the high refresh rate is available.
The counter-intuitive point is right there: it is the most powerful machine that displays worst. It is not a question of graphics performance, but of signal management.
Our technical analysis
The current version of macOS 26, combined with the Thunderbolt 5 firmware, limits the output of the graphics processor's DisplayPort channel. In the same move, high-rate DSC compression does not engage. Yet it is precisely DSC that allows a high-refresh 5K resolution to pass through the available bandwidth: without it, the system falls back on what it can carry uncompressed, that is 60 Hz.
On Macs with Thunderbolt 4 — the M4 and the base M5 — that mechanism does not come into play, and the monitor runs at full refresh rate.
This is not specific to our monitors
Two things confirm it. On one hand, manufacturers of Thunderbolt 5 docks now recommend sticking to 60 Hz monitors, for want of reliable behaviour beyond that. On the other, Apple itself has documented refresh-rate restrictions on certain Macs with its own 120 Hz display.
In other words: it is a platform limitation, not a fault in this or that monitor. We would rather tell you than let you conclude the monitor is at fault.
In practice
What to do depending on your machine
| Your Mac | Thunderbolt | High-refresh 5K | What we advise |
|---|---|---|---|
| MacBook Air M4 / M5 | TB 4 | Yes | Nothing to do, everything works |
| Mac mini M4 | TB 4 | Yes | Nothing to do |
| MacBook Pro M4 Pro / Max | TB 5 | To be checked on your configuration | Test before concluding |
| MacBook Pro M5 Pro | TB 5 | No — 60 Hz | Wait for the fix, or aim for resolution rather than refresh rate |
| MacBook Pro M5 Max | TB 5 | No — 60 Hz | Likewise |
| Windows PC | — | Yes | Not affected |
Observed in September 2026 on macOS 26. This behaviour depends on the version of the system and on the Thunderbolt 5 firmware: it may change with an Apple update.
Three ways round it, today
- Accept 60 Hz on 5K. For photography, editing, development or office work, 60 Hz is no hindrance: it is the refresh rate of the Apple Studio Display, including in its 2026 version. You keep the resolution and the Retina density, which are what count in those professions.
- Choose a high refresh rate in 4K rather than 5K. Apple documents 4K at 144 Hz on these chips. A P27ZB in 27" 4K, or a P32T in 32" 4K stay within the range stated as supported.
- Keep the monitor, change your mind later. A monitor is kept eight to ten years, a version of macOS a few months. If your monitor supports a high refresh rate, it will find it again the day Apple fixes Thunderbolt 5 compatibility.
What we will not do
We are not going to claim the problem comes from your cable or your settings. We tested with the supplied cable, connected directly, with no dock, and the same combination reaches 165 Hz on another machine. The factor that changes is the chip and its Thunderbolt.
We will update this page as soon as a version of macOS restores the expected behaviour. If you observe something different on your configuration, write to us: we document the cases as they come.
FAQ
M5 Pro / M5 Max and high refresh rates: frequently asked questions
Is my monitor faulty?
No. The same monitor with the same cable reaches 5K at 165 Hz in 10-bit on a MacBook Air M5. The limitation comes from the way macOS 26 and the Thunderbolt 5 firmware drive the DisplayPort output on the M5 Pro and M5 Max chips.
Why does the most powerful machine display worst?
Because it is not a question of graphics power. The M5 Pro and M5 Max distribute several DisplayPort tunnels per port to drive three or four displays. That sharing limits what a single monitor can claim, and DSC compression does not engage.
Does changing the cable fix the problem?
No. Our tests were conducted with the supplied cable, connected directly, with no dock. The same cable reaches full refresh rate on a machine with Thunderbolt 4.
Are M4 Macs affected?
No, not in our tests. Machines with Thunderbolt 4 — M4 and the base M5 — reach the high refresh rate normally.
What can I do in the meantime?
Three options: accept 60 Hz in 5K, which remains the refresh rate of the Apple Studio Display; opt for high-refresh 4K, which Apple documents as supported on these chips; or keep your monitor, which will regain its refresh rate as soon as Apple fixes Thunderbolt 5 compatibility.
A question about your configuration?
Tell us which Mac and which monitor you are using: we document the cases as they come and update this page.
Write to usPage written in September 2026 from our own tests. The specifications stated by Apple are those published at that date; this behaviour depends on the version of macOS and on the Thunderbolt 5 firmware and may change.