Macbook Pro M5Pro missing resolutions and refresh rate on external monitor

I recently bought a M5 Pro 14" MBP, when connected to my external display (LG 5k2k ultrawide, TB5 cable), this new Macbook is missing resolutions (and refresh rate) that I never had any issue using with other Macbooks.

I currently have 3 Macbooks here with me, right now:

M1Pro Macbook Pro: 3840x1620@100Hz, expected on M1P
M3Pro Macbook Pro: 3840x1620@165Hz, HDR available
M5Pro Macbook Pro: no option available for that resolution, no option for 165Hz (on any resolution), HDR available only on certain ones

I'll attach screenshots below. What is happening with this generation chip? I'm not the only one as I've read the same thing twice already on reddit.

M1 Pro:

M3Pro:

M5Pro:

[Edited by Moderator]

MacBook Pro 14″

Posted on Mar 19, 2026 9:54 AM

Top-ranking reply

andreeinprogress Author

Level 1

77 points

Posted on Mar 20, 2026 2:20 AM

Attaching some diagnostics differences between the M3 output and the M5 output (I will also open a radar).

From diagnostics on both Macs via `ioreg`:

Same monitor EDID is detected (`LG ULTRAGEAR+`, same serial/product identity).
Same link negotiation is achieved:

- DisplayPort over USB-C

- `LinkRateDescription = "8.1 Gbps (HBR3)"`

- `LaneCount = 4`

The high-refresh timing exists in the mode table on both Macs:

- `5120x2160 id=156 ... approx_max_hz=165.058`

However, on M5 Pro, system limits lower-refresh timing:

- `DPTimingModeId = 157` (`~100Hz` path)

While on M3 Pro, system reaches the 165Hz working state:

- `system_profiler` reports:

- `UI Looks like: 3840 x 1620 @ 165.00Hz`

- `Resolution: 7680 x 3240`

Looks in fact like a regression on M5 usb displayport bus, I don't think it has something do with Tahoe as the data on M1 (Tahoe) is pretty much the same as my M3 (Sequoia)

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80 replies

ThAune

Level 1

8 points

Mar 27, 2026 12:37 AM in response to ThAune

Using a high speed HDMI gives me 3840x2160 @60Hz. But with my ultrawide it should have been 3840x1620.

Going back to the original thunderbolt-cable from LG: back to 3360x1418 @72Hz..

Mar 27, 2026 1:24 PM in response to CleanCodeDeveloper

I just tested with an HDMI cable and another USB-C cable which came with the monitor. The font looks always blurry. HDMI results in 75Hz at max instead of up to 144Hz i connected through USB-C.

Apr 12, 2026 3:05 PM in response to andreeinprogress

I have this same issue with M3 Pro vs M5 Pro. I toggle between the two machine using the same cable. M3 offers 165hz while M5 is stuck on 100hz

Apr 16, 2026 9:15 AM in response to andreeinprogress

Congrats!

In the end, does your display still run at 100 Hz or 120 Hz? I wonder if my 72 Hz LG can be fixed using the same trick.

Apr 16, 2026 9:23 AM in response to andreeinprogress

At least we can be sure the issue can be fixed with a software update. Hopefully, Apple will release a fix in macOS 26.5 so we can all start enjoying our new MacBooks again.

Macbook Pro M5Pro missing resolutions and refresh rate on external monitor