Macbook Pro M5Pro missing resolutions and refresh rate on external monitor

I'm having similar issues with an upgrade from M2 Pro to M5 Pro. The current state is that the external display options for the M5 Pro do not match that of the M2 Pro. HDR, refresh rates, and display combinations that are and have been present on the M2 Pro simply are not there on the M5 Pro.

I have also noticed a change on the M2 Pro after the 26.3 update that the DisplayPort cable I had been using for 6 months would no longer output to my monitor. The cable tested fine on other machines.

I had returned the M5 Pro thinking I had a faulty unit (also got stuck in recovery mode with no wifi options for activation) and waiting on a replacement today.

I am using an Asus PG27UCDM monitor now connected over usb-c.

New M5 Pro arrived yesterday and I started a setup today.

With the recommended CableMatters 2.1 DisplayPort adapter and the DPI 80 cable (very short cable <3meters)

my M2 Pro will display all listed resolutions up to 240hz with HDR as expected.

The M5 fails to show refresh rates above 100hz specifically at 3360 x 1890 and 3200 x 1800, while it does show the HDR toggle throughout.

As the M2 Pro also has some new issues (crashing 3/4 times when switching refresh rates and/or HDR @ 3200 x 1800 and previously used cables no longer working,) I'm hoping this is a software issue and will be fixed soon, if we can get this thread noticed.

It's quite disappointing to find your new machine is incapable of doing what your old machine can during the very first steps of your "upgrade."

that LG 40WP95C display appears to be a 5K display 10 bits/color capable (HDR) at refresh rates up to 72 Hz

interfaces include

Thunderbolt 4

DisplayPort 1.4

2x HDMI 2.0

DIRECT DisplayPort 1.4 is limited to HBR3, 25.92 G bit/sec that at 10 bits/color HDR is limited to 50 Hz maximum before it starts to use Display Stream Compression to go higher.

DisplayPort-over USB cables (or USB-3 ports out of the Mac) is limited to top USB-3 display data speeds of 20 G bits/sec, which forces a drop back to the previous step HBR2 at 17.28 g bits/sec, supporting 5K directly at 30 Hz before Display Stream Compression is needed to go higher.

The display maker claims they include an ACTIVE ThunderBolt cable in the box. In theory, a DisplayPort-over-ThunderBolt connection should include DisplayPort 2.0 speed of UHBR10, 38.69 G bits/sec, but specifying DisplayPort 1.4 at HBR3 speeds of 25.92 is confusing.

If UHBR10 speed over Thunderbolt is Included, that means a 5K HDR display can achieve 60 Hz before it starts using Display Stream Compression to go higher.

HDMI 2.0 is 'stuck' at 14.4 G bits/sec speeds using PREMIUM or better cable, so one-cable HDMI operation is limited to 5K at 10 bits color at 30 Hz before display stream compression is needed. Two-cable operation is possible and well supported on the Mac side.

Most modern displays (except Apple XDR displays) support Display Stream Compression. When used to attain a modest data rate improvement, it is thought to be not visible to the naked eye. When applied more strongly, it may not be completely 'lossless'.

<< I'd like my (very expensive) professional machine to do so, given that my previous machines from the same line can do it without batting an eye.>>

Apple released a Tahoe update to version 26.4 in the last few days. be sure you are up-to-date.

Please let Readers know if that produces and different results for you.

I've been regularly submitting my crash reports from problems after the official Tahoe update (26.3) on my M2 Pro, ***, and I posted on Reddit linking this thread. The crash reports lately were all related to resolution or refresh rate changes on the M2 @ 3200x1800. I cannot say for certain this thread was the only reason I was contacted but they made mention of either attempting to contact the OP or intending to do so as well. The representative did speak about this thread specifically.

@Grant Bennet-Alder I see you do have a lot of experience here and I appreciate your help.

If you look at this being a hardware problem, this is a Massive issue. If this is a hardware issue and Apple has to deal with a broad recall, this is a very expensive mistake.

Apple brand loyalty is high for a reason and these machines are expected to be the very best available. For consumers receiving an M5 Pro or Max, finding it inferior in any way to previous products, especially those already in their ecosystem, is absolutely unacceptable. When you change only one component and your system doesn't operate correctly, 99% chance it is the one component you changed. There is no documentation suggesting otherwise and we based our purchases with the thought of improving our setups. The external monitor display capabilities is a major selling point and well boasted in the Macbook advertising and specs. As I stated already, I returned my first M5 Pro thinking there was an issue with that particular computer. I'm sure Apple doesn't want this to be a repeated behavior for all the consumers who use demanding external monitors.

[Edited by Moderator]

I recently bought my first MacBook M5 Pro and I can't make it work properly with my LG 38WN95C-W (3840x1600) display. What ever I try, the font is still blurry. The only way to get proper font rendering is to use my monitor with half of my native resolution (1920x800). This looks kinda ridiculous on a 37,5" Monitor and I lose more screen estate than I can effort to.

BetterDisplay does not help. I opened a discussion in the BetterDisplay Github and got confirmation that my display works just fine with older M-Processors. I do fear a regression as well and hope it is fixable.

I connected the monitor using an Apple Thunderbolt 3 (USB‑C, 0.8 meter).

<< It's tied to M5 Pro, not the port, because some users have reported that it works on the M4 Pro, which has the same Thunderbolt 5 port with DP 2.1. >>

there's a little more to it.

• The MacBook Pro M4 Pro Thunderbolt ports are generally Thunderbolt-5 ports, supporting overall speeds up to 120 G bits/sec maximum ONLY when connected to genuine ThunderBolt-5 peripheral devices. If not a Thunderbolt-5 device, port speed will drop back to Thunderbolt-4 speeds of 40 G bits/sec max.

• The M4 Pro Display Generators are limited to around 40 G bits/sec (with the HDMI Display generator slightly higher, about 42, but only when connected with an ULTRA rated cable to a device that supports HDMI 2.1.)

--------

• The MacBook Pro M5 Pro Thunderbolt ports are subject to the same limitations described above. You ONLY get faster speeds when the first device connected is a genuine Thunderbolt-5 device.

• The M5 Pro Display Generators are still MOSTLY limited to around 40 G bits/sec, but may be somewhat faster. It is difficult to tease out the exact speed increases from the cryptic description of what resolutions and refresh rates are supported, but it looks faster because it is not forced into two display-generator operation (dropping the number of supported displays) as quickly.

that Asus PG27UCDM display is a 4K display capable of 10 bits/color at refresh rates from 48 to 240 Hz.

interfaces include;

2x HDMI 2.1

DisplayPort 2.1

USB-C --- said to be 3.2 gen 1 (which is ambiguous)

-- If accurate, that is very similar to the original author's setup.

That display can do MUCH higher, and forcing the connection through USB is hobbling your performance.

Use direct HDMI or buy the CableMatters adapter ThunderBolt to DisplayPort.

<< Regardless what's the actual display specifications, >>

You can NOT disregard the display input specifications.

There are many factors that conspire to limit top data rates, including the capabilities of the display inputs, in combination with the limited number of 'steps' in output protocol speeds supported, in combination with limits on capabilities and length of input cables. Often, these factors compound each other to limit data rates.

At this writing, we have no compelling arguments thats suggest these new computers are on that list.

The main outstanding issue is crashing when forced into two display-generator operation at variable refresh rates and sometimes at top speeds.

It should be irrelevant up to 144hz with up to 2 4k monitors plus the laptop display.

I will attach some pics in clamshell mode with only the PG27UCDM display anyway.

You can see that there are options missing that have no documentation as to why.

Sometimes high refresh is available, sometimes not. Sometimes HDR is available, sometimes not.

The underlying issue being previous M series Macs are fully allowing these options.

I expected to run the M5 Pro with (2) 4k monitors @120hz with HDR and the laptop display easily.

I'm having the same issue. Just upgraded from a 2020 M1 Macbook Pro to a M5 Pro chip 16 inch.

Screen used is a LG 40WP95C. On the old Mac i could select a decent resolution. Now i have to use either 3360x1418 or 5120x2160.

Tried using BetterDisplay to add 3840x1620, but it won't show up in the list.

always_down wrote:

I updated to 26.4 and am having the same problems as well.

***On a positive note, Apple Support did reach out to me to collect some data and information so they are definitely looking into this problem.

Did you previously contact them directly?

if not, how did they know to ask?

I have the same issue, Macbook Pro M5 Pro cannot produce the 3840x1620 @hidpi from my Dell U4021QW - I am seriously disappointed. I tried BetterDisplay app, tried the Base64 thing below, tried a lot of things but nothing worked. Just 3360 or 5k and nothing in between. I was able to force the resolution through BetterDisplay but it would only display as lodpi (blurry text and poor quality display).

Gonna try the HDMI to HDMI cable suggested...but like others, really bummed that my Thunderbolt 4 cable that worked fine with my M2 Max will not work with a newer, 'better' computer...