PG27AQN 1080p/1332p resolutions displaying incorrectly in Apex/Fortnite/Valorant

[Kubose]

So me and a few other people online have noticed that some games (so far its been found in Apex Legends, Fortnite, and Valorant) trigger an incorrect monitor resolution/refresh rate in the 1080p and 1332p modes. (Aspect Control setting doesn't impact this issue) 

When set to 1080p/1332p with a DisplayPort connection, the PG27AQN is set to 1440p 144hz in these games, but only when the application is set to Fullscreen. 

In borderless windowed, it correctly uses 1080p/1332p 360hz. Also, this issue does not occur if any resolution other than 1080p/1332p is set. If you set the in-game resolution to 900p, the monitor runs 1080p 360hz even in Fullscreen. 

With an HDMI connection, the resolution works correctly, but is limited to 240hz at 1080p and 60hz at 1332p (assume this is due to the bandwidth limitation of the HDMI port)

I have little hope that this issue will be fixed, because so few people own this monitor that game devs will probably never patch for this specific issue on this specific screen. Also CRU doesn't work with DisplayPort on this monitor and I can't remove any resolutions manually, so I can't just fix it myself. From what I've seen online, this issue just gets the run around. Devs tell people to submit a report to the manufacturer, manufacturer tells people to submit a bug report for the game. I've kind of run out of ideas on what to try with this. 

[Jiaszzz_ROG]

Hello, @Kubose 

I apologize for the slightly delayed response.
May I ask for the brand, model, and driver version of the graphics card you are currently using?
Regarding the display, is it set to 1080p or 1332p and using a DisplayPort connection, but it displays at 1440p and 144Hz in full-screen games?
Does this issue only occur in games such as Apex Legends, Fortnite, and Valorant? Have you experienced the described issue in other scenarios, such as watching videos?
As for the limitations of the HDMI connection, we suggest referring to the user manual for guidance and observing its usage.

Based on your description, we would recommend cross-testing with another monitor to observe the gaming performance or trying different display resolutions in other games.

Thank you.

[Kubose]

My GPU is an Nvidia RTX 4090 (specifically MSI Suprim Liquid X) running driver 531.79. 

Issue only occurs in three known titles (Apex, Fortnite, Valorant), but there may be more that haven't been discovered yet. These resolutions work as intended in the OS, only Fullscreen in these games have the issue. 

The best way I can think to describe this issue is that the 1080p and 1332p DisplayPort resolutions on the monitor interact poorly with some games in their Fullscreen mode, causing the monitor to set itself to 1440p 144hz as seen in the monitor's OSD (personally I have tested and found this in Apex Legends and Fortnite, but researching the issue, I have found posts from people having the same issue in Valorant on this display). No other resolutions are effected, only 1080p and 1332p, and it does not occur with an HDMI connection.

Weirdly, when I connect the DisplayPort cable to my iGPU (Intel UHD 770), this issue is still present, but the effected games Fullscreen modes cap the monitor at 1440p 240hz rather than 144hz. 

I recently came from a 1440p 240hz Samsung G7 Odyssey that did not have this issue. 

My (probably baseless) assumption is that certain games are reading these two resolutions (1080p/1332p) wrong from the monitor (or vice versa), causing the monitor to fall back on 1440p 144hz as a default for an unsupported resolution (which would explain why borderless doesn't have the issue, in borderless the game is taking the resolution from Windows, which works fine). 

These resolutions are the two the monitor specifically asks for when using the 25 Inch Aspect Control mode, so they might be configured in the monitor itself in a way that isn't accounted for by some games (My reason for thinking this is because only these two resolutions are effected). 

But that is just my guess, I've tried everything I can think to try (CRU (doesn't work with DP on this screen), Borderless ("works", but adds input lag and decreases in-game performance), HDMI (bandwidth limited), iGPU DP (only hits 240hz)). 

Really the only thing that works is not using 1080p/1332p in these effected games, but it is not ideal because that means that I can't use the 25 Inch mode as intended (1332p) in 3 of the biggest esports games on the market.

[Jiaszzz_ROG]

Hello, @Kubose .

We appreciate the further details.
If possible, please provide a complete recording of the situation, including OSD settings, Windows Display settings, and any differences observed in-game.
However, based on the current description, we recommend contacting the relevant game publisher for further inquiry and clarification of the situation.
I will also forward your feedback to the appropriate department for reference and confirmation, and I suggest you continue to monitor the situation.

Thank you.