Compatibility · Updated on 17 October 2026
MacBook Pro M5 Pro and M5 Max: why your high-refresh monitor is stuck at 60 Hz
The same monitor, the same cable: 5K at 165 Hz in 10-bit on a MacBook Air M5, but 60 Hz on a MacBook Pro M5 Pro or M5 Max. It is not the monitor, and it is not only ours: owners of LG and Samsung monitors, and even of Apple's Studio Display XDR, report the same kind of problem on these chips. The good news: macOS 27 Golden Gate should normally fix it. Here is what we measured, what other users report, and what to do if the problem persists.
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: over Thunderbolt, the refresh rate falls back to 60 Hz, with no way to select anything better.
- Macs with Thunderbolt 4 (M4, base M5): 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 how the video signal is handled.
Not specific to Kuycon
LG, Samsung, Apple: other users report the same thing
Since spring 2026, owners of M5 Pro and M5 Max Macs have been reporting similar problems with monitors from other brands. Some documented cases:
- LG 45GX950A (5K2K ultrawide, 165 Hz): on an M5 Pro over USB-C / Thunderbolt, 165 Hz is missing and the Mac falls back to about 100 Hz, while an M3 Pro reaches 165 Hz on the same monitor. Through the Mac's HDMI port, 165 Hz works. The Apple Community thread has more than 80 replies since March 2026, and participants suspect a regression in the way the M5 Pro handles DSC compression.
- Samsung Odyssey Neo G9 (7680 x 2160): on an M5 Max through a Thunderbolt 5 dock, the native resolution cannot go above 60 Hz, whereas an M4 Max drove the same monitor and the same dock at 120 Hz with HDR. Through the Mac's HDMI 2.1 port, 120 Hz with HDR works.
- 5K 165 Hz and 4K 160 Hz monitors: on an M5 Pro, the refresh rate is correctly selected in System Settings, but moving windows and scrolling look like 60 Hz. Reported on the Apple Developer Forums between July and September 2026.
- Apple Studio Display XDR at 120 Hz: on an M5 Pro, scrolling is choppy at 120 Hz or in Adaptive mode, and smooth at 60 Hz. Even Apple's own display is affected.
In other words: it is a problem of the platform, not a fault in this or that monitor. We would rather tell you than let you conclude that your monitor is at fault.
Two different problems, often confused
- 1. The refresh rate is not offered. System Settings caps at 60 Hz (sometimes 100 Hz) over USB-C / Thunderbolt. This is the case we measured. The most likely explanation, shared by many users, is that DSC compression does not engage properly over Thunderbolt on these chips. DSC is what lets a high-refresh 5K signal fit into the available bandwidth: without it, the Mac falls back to what it can carry uncompressed, that is 60 Hz.
- 2. The refresh rate is offered, but the image stutters. 120 Hz or 165 Hz is displayed and the cursor is smooth, but scrolling and windows jerk. Measurements published by a user show that while scrolling, the graphics processor of the M5 Pro stays at a very low frequency (around 340 to 390 MHz) and misses part of the frames: at 120 Hz, only about 70% of the frames arrive on time, against 98% at 60 Hz.
In practice
What to do depending on your machine
| Your Mac | Thunderbolt | High refresh rate over Thunderbolt | 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 to 100 Hz | Update to macOS 27 Golden Gate, otherwise use the HDMI port |
| MacBook Pro M5 Max | TB 5 | No, 60 Hz | Update to macOS 27 Golden Gate, otherwise the HDMI 2.1 port restores 120 Hz in the reported cases |
| Mac mini, Mac Studio M5 Pro / M5 Max | TB 5 | Not tested by us, same chips | Same advice |
| Windows PC | - | Yes | Not affected |
Observed in September 2026 on macOS 26, updated on 17 October 2026. This behaviour depends on the version of macOS and on the Thunderbolt 5 firmware: macOS 27 Golden Gate should normally fix it.
How to get the full refresh rate back
Update to macOS 27 Golden Gate
This is the expected fix. macOS 27 Golden Gate, released on 14 September 2026, improves external display support: Apple cites 5K at 120 Hz on ultrawide monitors, and one user reports that it restored the native resolution and the full refresh rate of an LG 40-inch ultrawide. Make a backup, install the update from System Settings, General, Software Update, then check the refresh rates offered in System Settings, Displays. If the problem persists, install the next macOS 27 updates as they come out.
Use the Mac's HDMI port
If the problem persists after the update, this is the most reliable workaround reported. With an Ultra High Speed (HDMI 2.1) cable plugged directly into the Mac's HDMI port, users got back 120 Hz on a Samsung Neo G9 and 165 Hz on an LG 45GX950A. It only works if your monitor has an HDMI 2.1 input: check in its manual the maximum refresh rate over HDMI, which can be lower than over USB-C or DisplayPort.
BetterDisplay, for experienced users
This third-party app (BetterDisplay) can make macOS read the description (EDID) of another monitor. Several users recovered 120 Hz this way on LG ultrawides, without HDR; on another model, it only worked at 60 Hz. It is not an Apple tool: if the screen shows an out-of-range message, go back to 60 Hz.
If the refresh rate is shown but the image stutters
M5ScrollBoost, an experimental open-source utility described in the Mac Anorak article listed in our sources, keeps the graphics processor at a higher frequency while you scroll. It is not supported by Apple and slightly increases power consumption. Otherwise, setting the display to 60 Hz gives a perfectly regular image.
Choose between resolution and refresh rate
At 60 Hz, a 5K monitor keeps its full resolution and its Retina density, which is what counts for photography, editing, development or office work: it is also the refresh rate of the Apple Studio Display. If refresh rate is your priority, a 4K monitor stays within what Apple documents on these chips: the P27ZB in 27-inch 4K or the P32T in 32-inch 4K.
Report it to Apple
Through the Apple feedback page or the Feedback Assistant app, giving your Mac model, your monitor, the connection used and your macOS version. The more detailed reports Apple receives, the faster a fix gets prioritised.
What we will not do
We are not going to claim that 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 the fix is confirmed on our own test configuration. If you observe something different on your configuration, write to us: we document the cases as they come.
Sources
Our sources
Reports from users and specialist sites, consulted on 16 and 17 October 2026. The links open in a new tab.
- Apple: MacBook Pro - Tech Specs, external display support of the M5 Pro and M5 Max chips.
- 9to5Mac, 9 June 2026: macOS 27 Golden Gate adds higher resolution support for ultrawide displays, Apple's announcement of better ultrawide display support in macOS 27 Golden Gate (5K at 120 Hz).
- Apple Community, March to September 2026: MacBook Pro M5 Pro missing resolutions, LG 45GX950A without 165 Hz over USB-C, HDMI and BetterDisplay workarounds, macOS 27 feedback.
- Life in Tech, 26 March 2026: M5 Max USB-C regression, Samsung Odyssey Neo G9 limited to 60 Hz over Thunderbolt and 120 Hz over HDMI 2.1 on an M5 Max.
- Apple Developer Forums, July to September 2026: Apple Developer Forums thread 837513, 5K 165 Hz and 4K 160 Hz monitors that stutter on an M5 Pro.
- Mac Anorak, 7 October 2026: Studio Display XDR scrolling stutter on the M5 Pro MacBook Pro, measurements on the Studio Display XDR and the M5ScrollBoost utility.
- Michael Tsai, 9 October 2026: macOS 27 and external displays, summary of the current reports.
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, and owners of LG and Samsung monitors report the same limitation on M5 Pro and M5 Max. The problem comes from the way these Macs drive their USB-C / Thunderbolt video output.
Are only Kuycon monitors affected?
No. Similar reports concern the LG 45GX950A, the Samsung Odyssey Neo G9, 5K 165 Hz and 4K 160 Hz monitors, and even Apple's Studio Display XDR at 120 Hz. Our sources are listed on this page.
Does changing the cable fix the problem?
Changing the USB-C or Thunderbolt cable does not: our tests were run with the supplied cable, connected directly, with no dock. On the other hand, switching to the Mac's HDMI port with an HDMI 2.1 cable restored the high refresh rate in several reported cases, provided the monitor has an HDMI 2.1 input.
Are M4 Macs affected?
Not in our tests: Macs with Thunderbolt 4, M4 and base M5, reach the high refresh rate normally. A few users report resolution and refresh rate problems with ultrawide monitors on an M4 Max, so it is worth testing your own configuration.
Has Apple fixed the problem?
Normally yes, with macOS 27 Golden Gate, available since 14 September 2026: Apple announced better support for external displays, and users report that the full refresh rate came back after the update. The release notes do not name this exact bug and a few users still see stuttering, so we will confirm on this page as reports come in.
What can I do in the meantime?
First, update to macOS 27 Golden Gate. If the problem persists: connect the monitor to the Mac's HDMI port with an HDMI 2.1 cable, try BetterDisplay if you are an experienced user, and use M5ScrollBoost if the refresh rate is shown but the image stutters. Otherwise, 60 Hz in 5K keeps the full resolution, and a high-refresh 4K monitor stays within what Apple documents.
A question about your configuration?
Tell us which Mac, which monitor and which connection 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, updated on 16 and 17 October 2026 with the reports of other users and specialist sites and the arrival of macOS 27 Golden Gate. 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.