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Help I've got a issue with Dual Monitors on my 2023 Mac Pro M2 Ultra

I have this Mac and Monitors…


2023 Mac Pro

Apple M2 Ultra with 24-core CPU, 60-core GPU, 32‑core Neural Engine

64GB unified memory

Main Mac Storage 8TB SSD

With Two Separate PCIe Cards Storage 24TB SSD for Movies & Video (24TB per PCIe Card, so 48TB in all)


I’m running macOS Sequoia - Version 15.0.1


My Main Monitor: ASUS ROG Swift PG43UQ


(ROG Swift PG43UQ DSC Gaming Monitor — 43-inch 4K UHD (3840 x 2160), 144Hz,

G-SYNC Compatible, DSC, DisplayHDR™ 1000, DCI-P3 90%, Adaptive Sync, Shadow Boost)

https://www.amazon.co.uk/ASUS-Swift-PG43UQ-Gaming-Monitor/dp/B083QYQQ5Y/ref=cm_cr_arp_d_product_top?ie=UTF8


My Secondary Monitor: Sony BRAVIA XR XR-55A80L 55 Inch OLED 4K Smart TV

https://www.amazon.co.uk/Sony-XR-55A80L-Perfect-PlayStation5-Surface/dp/B0BX449WWF


Now before my 2019 Mac Pro strangely died and got replaced with my 2023 Mac Pro M2 Ultra I never had any issues with having Dual Monitors. After a few months of having my awesome 2023 Mac Pro M2 Ultra I had a issue where my Secondary Monitor would flicker on and of so I naturally I assumed it was a loose cable connection or a faulty HDMI etc. So when I realised it wasn't a loose connection I bought a new HDMI and no luck so bought a few more think it was a few faulty HDMI's but no, however the issue slowed down it my Secondary Monitor hardly went off but 2 Operating Systems later the problem gets worse. I often leave my Mac on over night as I often have work in process etc. but I turn off both screens but in the morning sometimes my Mac wont see my Secondary Monitor / TV, at the time I had a odd fix where i turned off and on the HDR setting on the Mac. However that trick stopped working and whenever my Mac doesn't recognise my Secondary Monitor the only way my Mac can see it is if I restart it.


My mate once told me its a common issue so is there a fix to this annoying problem. I've had Dual Monitors on most of my Macs but I've never had this issue so I hope you can help me.

Mac Pro, 15.0

Posted on Oct 18, 2024 11:51 AM

Reply
30 replies

Oct 25, 2024 9:58 AM in response to Grant Bennet-Alder

Hi sorry for the delay first things first I think my main screen flicker is fixed. However my TV has 4 HDMI's in it and I switch sources like between PS5 or PS4 or Mac, last night I was on my PS5 but I left my Mac on and when I selected Mac on my TV it didn't recognise it again so I had to restart my Mac again then it saw it. so the new HMDI seemed to fix the flicker but not the main issue of my Mac not recognising my second screen. as there a way for my Mac to always recognise my second screen?


Next yes I tried to calibrate with the ASUS display profile while it on HDR and it was practically pointless it hardly changed and the only thing I can change is the warmth of the colours and I dont want that. I'm thinking of buying this to actually adjust the colours how I want and vidid and not pale as if it wasn't on HDR https://apps.apple.com/gb/app/gamma-control-6/id1250521285?mt=12

Heres a screenshot on HDR and everything is pale


Here's a screenshot HDR is off colours nearly there



And this is the colour profile off HDR which is perfect. I just want it do look like this on HDR


Oct 25, 2024 1:11 PM in response to KainsTorment

You don't have to understand ANY of what I wrote directly above.


There are four ways to DEFINITELY get your display to show up, right in those four bullet points. Any one of them will do the trick for you.


RE: getting the colors you like to see.

you should start a new discussion with a title that will attract the readers you want to hear from. This very long thread has a title about how to connect.


Start a NEW discussion


.

Oct 19, 2024 7:04 AM in response to KainsTorment

there is no special connector for HDMI 2.1. It should be completely indistinguishable in every way, except for a tag attached to the cable.indicating it is certified.


There is a High Retenion Force connector on some cables, that does not follow the advanced protocols -- any cable could have this connector. it has a very slightly different look, but should be completely interchangeable as well. The places where the extra hooks go

... is reserved for exactly this purpose.


Oct 20, 2024 10:14 AM in response to Grant Bennet-Alder

I've attached a photo of the back of my Mac and I'm even more confused as you can see theres no DisplayPorts at all the Mac came like that. The only things I've added are 2 rows of USB PCIe's and 2 rows of 24TB SSD's. Unless I'm being really thick here there's absolutely no DisplayPorts 1.4 on my Mac.




As you can see I only have 2 HDMI's and a fw Thunderbolt 4's for screens.


I'm a gamer, artist, musician and film maker so I love my big screens and I really dont like PIcture-in-Picture or spit screens.

Oct 20, 2024 10:40 AM in response to KainsTorment

<<. there's absolutely no DisplayPorts 1.4 on my Mac. >>


correct as written. No DIRECT displayPorts. however, DisplayPort protocol can be adapted from any of the ThunderBolt ports on your display cards or on the chassis.


The usual way to obtain a DisplayPort connection is with a ThunderBolt-to-DisplayPort adapter/cable like this one:


Monoprice USB-C to DisplayPort Cable - 32.4Gbps Active 8K60Hz Thunderbolt 4/3 Compatible, Black, 3ft Product # 24443 - $11.99




...

Oct 18, 2024 12:01 PM in response to KainsTorment

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:


"Premium High Speed HDMI cable" or that + "with Ethernet" --OR--

"Ultra High Speed HDMI cable" or that + "48G"


Cables with No Certification tags are good for your standard 720p TV set, and not much more.


Oct 19, 2024 6:00 AM in response to Grant Bennet-Alder

Sorry for the delay I tried to reply on my iPad but it wouldn't send for some reason.


I've always bought HDMI's that say 4K high speed on them.


in the past I've bought the cables you suggested like this https://tinyurl.com/Click-Here-To-See-HDMI However in the past I've found out is a cable says "HDMI 2.1" then the plug wont fit in the back of my Mac, I could be wrong but I heard Macs cant have HDMI 2.1? So could you please give me a link to get the suitable HDMI's that I need please as I always seem to get the wrong ones? If it works then I'll get 2 for both my monitors. I'm from the UK, thanks for your help I really appreciate it.

Oct 19, 2024 11:33 AM in response to Grant Bennet-Alder

I've never seen those hooks on any HDMI before.


Actually yes I have very occasional blank screen flicker on my main screen the ASUS ROG Swift PG43UQ


(ROG Swift PG43UQ DSC Gaming Monitor — 43-inch 4K UHD (3840 x 2160), 144Hz,

G-SYNC Compatible, DSC, DisplayHDR™ 1000, DCI-P3 90%, Adaptive Sync, Shadow Boost)

https://www.amazon.co.uk/ASUS-Swift-PG43UQ-Gaming-Monitor/dp/B083QYQQ5Y/ref=cm_cr_arp_d_product_top?ie=UTF8


However the ASUS was second hand but practically new so I assumed this was the reason for the occasional blank screen flicker?


On my main screen the ASUS the highest res I can have is 3840x2160 at 60 Hertz and I have HDR turned on. I have the same on my Sony TV ie the highest res I can have is 3840x2160 at 60 Hertz and I have HDR turned on this is the Mac settings, but my TV / 2nd monitor is the is the many issue here.


I've just seen on Google my mac can now have HDMI 2.1 :) so if true can you link me the proper HDMI that I need to buy please?

Oct 19, 2024 12:40 PM in response to KainsTorment

On your main screen, running data rates that high runs smack into the limits of switching speeds for electronic devices. cable length too long cause transmission errors, and the display can flicker or blink completely off. This means cable lengths are limited to one meter from the computer to the DisplayPort adapter electronics.


In most cables that is the total length of cable allowed, but the ACTUAL limit, if you had a cable that looked like a snake that just had lunch, is one meter TO the converter electronics, and one meter after the converter to the display.

Oct 19, 2024 12:49 PM in response to KainsTorment

if you limit your HDMI display to strictly HDMI 2.0 speeds it uses the same signaling method used by EVERY HDMI connection, but tops out at around 4K at 60 Hz.


Once you exceed that limit, EVERYTHING changes to use HDMI 2.1 rules. The Signals in the cable are re-assigned, the encoding method is different and if you don't have "ULTRA" rated cables, it does not work at all.


But the HDMI authorities are quiet when it comes to maximum cable length. Every other interface running at these high speeds, and using that modulation technique (admittedly HDMI is using higher Voltages, but the same signaling) is limited to one meter of cable. I can't cite an authority that says it MUST be that way, but it would be prudent to reduce your cable length when using HDMI 2.1 to one meter or less.

Oct 20, 2024 1:46 AM in response to Grant Bennet-Alder

My main 43” ASUS screen is about a foot away from my 2023 Mac Pro so a short HDMI is easy. Although my ASUS has a DisplayPort my Mac sadly hasn’t so that’s why I use HDMI’s.


For my 55” Sony TV it’s right next to my ASUS screen but annoyingly the inputs are on the far side of the TV so I have no choice but to have a 3 meter HDMI.


So like I asked before could you please link me a ultra HDMI 2.1 or whatever I need for the TV please as I’ve bought the wrong thing in the past.


Actually I’ve just realised I’ve still got my HDMI to Thunderbolt 3M from when I used to have my old 2019 Mac Pro, would that do for the TV?


PS I’ve just realised my ASUS isn’t HDMI 2.1 but my TV is

Oct 20, 2024 8:03 AM in response to KainsTorment

I would test the shortest and best HDMI to HDMI cable that I had connected to the 43" ASUS.

Or optionally get a short high speed USB-C/TB to DisplayPort cable to connect the 43" ASUS.

for example > https://www.amazon.com/dp/B0CSJQY34N/ref=twister_B0CPFKZ5KH?_encoding=UTF8&th=1


Then I would test the USB-C/TB to HDMI cable that you used with the 2019 connected to the 55" Sony TV.

Or optionally test the best 3 meter HDMI to HDMI cable that I had connected the 55" Sony TV.

Oct 20, 2024 8:15 AM in response to KainsTorment

for your main display is 4K with HDR 10-bit capability.


I/O PORTS

DisplayPort 1.4 DSC

x 2

HDMI (v2.0)

x 2


using ONE DisplayPort adapter/cable limited to 1 meter length, that can support 4K at 96Hz. The date rate HBR3, a very fast 25.92 G bits/sec, and faster than MOST Mac USB port,s but not faster than the ThunderBolt ports on the Mac Pro 2023.


using ONE HDMI 2.0 premium rated cable of longer length, you can get 6K at 50 Hz, before the data format is downgraded and dithering is used to make uptake shortfall in bandwidth. This is operating a t 14.4 G bits/sec.


One HDMI 2.1 cable switches to a different data encoding and clocking, must be ULTRA/48G rated,, and runs at 42,5 G bits/sec with no compromises EXCEPT the suggestion (not statement) that length may be limited.

Help I've got a issue with Dual Monitors on my 2023 Mac Pro M2 Ultra

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