Studio Display XDR + M5 Pro MBP : scrolling stutter at 120Hz

[tiguanito]

I'm running into an issue with my new MacBook Pro M5 Pro (14" 18 CPU /20 GPU - 48GB) hooked up to a Studio Display XDR and wanted to see if anyone else is seeing this.
UI scrolling across all apps is noticeably choppy when the XDR is set to 120Hz or Adaptive (47–120Hz), especially during web browsing. The MacBook’s internal screen is smooth, and the stutter happens whether the MacBook lid is open or closed in clamshell mode.

Details on my setup:
- MacOS 26.6.2 (latest)
- XDR firmware 26.4, connected directly via Apple Thunderbolt cable (already tried power cycling).
- Happens with both the internal trackpad and an MX Master 4
- Tested the exact same XDR setup with a base M5 and an M5 Max: both were smooth at 120Hz. Seems oddly specific to the M5 Pro chip.
- Tested with a second (work) MBP M5 Pro and reproduced the exact same stuttering behavior, pointing to the M5 Pro chip variant.
- Choppy with Safari and Chrome browser.

Is this a known macOS display driver bug on the Pro chip ? I hope it's not a HW bug. I can still return it but don't want to spend an extra $1k+ in a Max just for that reason.

 

[DavidPS]

Since you reproduced it on a second M5 Pro and two other chip variants were fine on the same XDR, that really does smell like a driver/refresh-rate bug rather than your unit being defective, so I wouldn't burn $1k on a Max over it yet. A couple of things worth isolating first: set the XDR to a fixed 120Hz instead of Adaptive, since the variable-refresh ramping is where a lot of the reported choppiness comes from, and see if the stutter changes character. Then check whether it's actually the display pipeline or the scroll pipeline by opening a WindowServer-heavy test — drag a window around, or scroll something native like Finder in list view — versus a browser page. If only browsers stutter, it's more likely the browser's own frame pacing than the GPU driver; Safari's built-in scrolling and Chrome's compositor behave differently at 120Hz. Also try knocking the resolution down one scaled step temporarily: if it goes smooth, you're looking at a bandwidth/scaling issue, not silicon. If nothing helps, file it with Feedback Assistant with a screen recording and note the three-chip comparison, because that's exactly the kind of detail that gets a display bug triaged. Your return window is the safety net, but I'd give it one OS point release before assuming hardware.

 

[tiguanito]

Thanks for the suggestions.
XDR to fixed 120Hz : no improvement
lowering display resolution : no improvement
Native UI (find in list view, etc): Finder in list view : same choppy scrolling behavior across every multi-page application.

I'll report the issue with the Feedback Assistant. I could also try the macOS 27 Beta I suppose.

 

[tiguanito]

Filed the feedback ticket FB24598596
I've just reproduced on a clean, secondary APFS volume running macOS 27 Beta (Build 26A5425a = today's build) with no third-party software, extensions, or restored user profiles.