PG27AQN doesn't output 360Hz with 3 monitors

[PuppetMaster000]

To give all my specs first:

I have the PG27AQN as main monitor, a 240Hz PG279QM and a 165Hz PG279Q as secondary monitors. All 3 are 2560x1440p monitors.

I run an Asus ROG Strix 4090 with an Intel i9 13900k.

I use the cables that came with the monitors as well as KabelDirekt DisplayPort Cables that can be found here:

https://www.amazon.com.au/gp/product/B07HL7RSRW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

No matter what I try, as long as all 3 monitors are connected, the PG27AQN refuses to output 360Hz. Color depth doesn't matter as I tested both 8 and 12bpc and they crash.

If it is 240Hz it does fine, 2560x1440 with 12bpc, all good, without issues. 3 monitors at 240/240/165 works good too, no issues. Dual monitor 360Hz and 240/165Hz works fine as well, it doesn't matter, no issues.

But the moment all 3 are connected and I try any configuration with 360Hz, be it 360/240/165, 360/144/144 or 360/60/60, it will crash the video output and my PC and I am forced to force restart. I opened up a case and had a representative tell me he will get back to me, then proceeded to ignore me for 3 weeks.

The PG279QM I have I paid 600$ (Australian) less for than the PG27AQN and they are basically functioning the same right now because the monitor doesn't work at 360Hz. Can anyone please help?

[Jiaszzz_ROG]

Hello, @PuppetMaster000 

We apologize for any inconvenience caused.
Please assist us in confirming the following questions:
- Has the ROG Swift 360Hz PG27AQN's main screen been updated with the firmware released on May 26, 2023?
- When connected individually, can the ROG Swift 360Hz PG27AQN's screen output at 360 Hz?
- Are the three monitors directly connected to the graphics card via DP?
- Is the graphics card connected to the motherboard through an adapter?
- When the monitor crashes, what specific scenarios occur?
For example, does the ROG Swift 360Hz PG27AQN show no display or fail to turn on (do the indicator lights remain on?)?

If possible, please provide a comprehensive recorded video of the problematic scenarios, including any changes in settings leading to crashes as well as the troubleshooting steps you have taken following the crashes.

Thank you.

[PuppetMaster000]

Hi Jiaszzz, here are all the answers to your question:

- If you mean the GPU driver, I have the latest 536.40 released June 29, 2023. If it is a monitor driver you are talking about, I don't know where to get it from as the latest one on the website is October 31, 2022
- When I have 2 monitors connected, it can output 360Hz. Regardless of which monitor is connected together with it
- All 3 monitors are connected with a DP to the graphics card directly
- The graphics card is connected directly to an Asus ROG Maximus Z690 Formula in the first slot
- I change the refresh rate either through the Nvidia Control Panel or through windows settings (both result in the same outcome) and the moment I click apply, all the screens go dark, show the no display output message and the PC becomes unresponsive. Normally if you don't confirm and accept the changes it should revert back to the previous configuration after 15 seconds but in my case that doesn't happen and I am forced to physically restart the PC with the button. This is my biggest issue as restarting it this way is not good for the PC, so I can' just do it 100 times over.

Here is a video of the issue:

I have explained the scenarios and attempted fixes in the first post. Long story short I tried to match the 2 side monitors because I thought 3 different refresh rates might be the cause, they weren't. I tried lowering both to 60 fps too, nothing. I tried maxing both refresh rates to have the least amount of difference because I thought that might be the cause, nothing. I tried swapping around positions on the GPU without success. Lowered the color depth and resolution without success.

Basically, there should be no reason my configuration can't output 3 monitors at 2560x1440 resolution and max refresh rates for each (those being 360/240/165) but for some reason the moment a third one is added to the mix, the 360Hz gets effectively disabled.

[PuppetMaster000]

I just managed to get it to work somehow. I don't even know exactly how but here is what I did:

I found a post from one guy talking about DSC and how his monitor would only display 360Hz with 2 monitors if he connected it to the GPU port furthest from the motherboard. But when he connected it to the one closest to the motherboard he could do 3 monitors at 360/165/165.
I tried this and it didn't work at first but after several attempts it finally worked. I lowered my two side monitors to 144 Hz, toggled the main one to 360 and it didn't crash. Then I slowly raised the 2 side monitors to 360/200/144, then 360/200/165 and finally to 360/240/165.

All of them are connected with display ports, 2560x1440 and the PG27AQN is at 12bpc color output. Which is supposedly not even possible. I don't know why, how or what happened nor how it works and all I am hoping for is that this setup isn't a ticking time bomb that will crash or have severe issues in the future. Don't know if it will get destroyed when a new GPU driver gets released.

Does Asus have any clue regarding why this is happening?

[pg27aqnowner]

There is a note in the nvidia driver release notes specific to 30 and 20 series cards stating using DSC limits the GPU to two displays. I do not know if this is simply an old note that's been in the release notes for months and they haven't updated it or if they intend to mean the issue should not exist on a 40 series card.

[PuppetMaster000]

Yeah this was the reply I got from Asus as well which shouldn't apply here since I have a 40 series card.

Furthermore the fact that the monitor manages to work somehow despite these supposed limitation, based on which port on the GPU it is plugged into is the most confusing part.

I am contemplating if I should return the monitor or just deal with it as is.

[ItsmeNevs]

It's totally stupid to do anything with this monitor, I think.
I have the monitor aam 1 port of my 4090 connected the 2 monitor (An Alienware 2k 240 HZ) at the last port. since the Asus monitor is on the system there are in the video (stream amazon prime video) jerks / lags and more. it makes so no sense / fun what to do on the computer and that with 2 monitors with me. either there must be something fixed in the software or this monitor is zero mature that he can run without problems. it's a real pity in the esport setting it makes real fun to play games the performance is top.
even if I set the Alienware monitor to 60 HZ there are the problems.
wen I do not get this fixed in the next 5 days the monitor goes back and stay away from Asus. to save me the stress really too bad

[PuppetMaster000]

For anyone that stumbles on this in the future I hope this will help. I talked to Nvidia and they gave me information that Asus doesn't know about apparently. Long story short, this monitor needs to use something called DSC to output the required 360Hz. When a GPU detects this mode is used (it is used automatically when setting the monitor to 360Hz), it basically registers two of your GPU ports are used for the DSC monitor. What this means in short is that even something like a ROG Strix 4090 with 3 display ports can only output 2 monitors if one of them is a DSC monitor. Here is a link to the article from Nvidia:

https://nvidia.custhelp.com/app/answers/detail/a_id/5338/track/AvOArwpVDv8S~UL4Gv0e~yJlb9UqbC75Mv_4~...

TLDR: Don't buy this monitor if you plan to use more than 2 monitors in your setup!