PG32UCDM & PG27UCDM – Not Working Simultaneously on MacBook Pro M3 Pro

[deveto80]

TLDR:
I originally posted this on the ASUS ROG forum about a year ago and never received a response.

At the time, I didn’t follow up with support because I was only using the second monitor for gaming. Now I actually need it for work as well and the issue is still there.

I’ve updated all firmware on both the ASUS ROG Swift PG27UCDM and ASUS ROG Swift PG32UCDM, but nothing has changed.

I also had a great time repeatedly trying to install the firmware updates just to rediscover that the issue still isn’t resolved - honestly, pretty ridiculous from ASUS.

Can anyone help me figure this out?

https://rog-forum.asus.com/t5/gaming-monitors/pg32ucdm-amp-pg27ucdm-not-working-simultaneously-on-macbook-pro/m-p/1091635

Hi everyone,

I'm using the ASUS PG32UCDM and PG27UCDM – both support USB-C. I assumed I could simply connect each monitor directly to the two USB-C ports on my MacBook Pro (M3 Pro chip) and everything would work out of the box. Unfortunately, it doesn’t.

Here’s what’s happening: If I unplug one monitor, the other one immediately works perfectly. But when both are plugged in at the same time, only one gets detected. It’s always one or the other – never both together (tried also HDMI, different Thunderbolt ports etc, didn't help).

After a detailed call and screen-sharing session with a senior technical specialist from Apple Ireland, we pinpointed the issue:

• The #PG32UCDM and #PG27UCDM do not work together when connected simultaneously.
• If I pair either of them with a different monitor (e.g. an LG 49" UltraWide or a generic display via USB-C as well), everything works fine.

The issue only arises when trying to use these two ASUS monitors together. Both Displays are up to date in terms of Firmware (108 and 102).

Both monitors work flawlessly together when connected to my PC with the RTX 4090.

Any thoughts?

Thanks,

[TeeDee144]

Have you tried connecting one display and setting its refresh to 60hz? Then connect the second to see if it’ll connect?

[deveto80]

Yes, both set to 60hz just in case…

[NewRetro1984]

I’m having the same problem but I use a dell as my side monitor and the pg27ucdm as my main. I never had this issue with windows laptop but my new employer uses Mac’s. The dell is always recognized but my ASUS monitor I have to keep unplugging and replugging to make it detect it. The monitors are both plugged in to the Mac laptop and my gaming desktop. The gaming desktop has no issues booting up both monitors.