Question 4090 suddenly can't use three DP at the same time? All ports work though

[steventhehro]

Everything was fine last night.

Been using 3 monitors via the 3 display ports for going on 2 months, and then suddenly I can't. Two can be active, and all three are registered in windows, but if I select the third one and try to move it from "disconnect" to "extend" in display settings or in Nvidia CP, it freezes my whole PC. Soon as I unplug the DP cable, it unfreezes.

- This happens with new or old cables
- This happens regardless of which DP port on the 4090 it's plugged into
- I've tried reinstalling drivers (3x with clean install and tried using DDU).

If I use HDMI it's fine, and the monitor cuts right now, but my third monitor (VG248QE) doesn't support 144hz via HDMI or else I'd just say screw it and do that.

I'm using:
- Samsung Odyssey G7 1440p 240hz
- 2x Asus VG248QE 1080p 144z

 

[Lutfij]

Manually set all displays to 120Hz, turn off Adaptive/Free/G-sync. I had a similar issue with a friend who had 3x144Hz panels in 4K on an RTX4090 FE card. Same thing happened with an Asus RTX4060Ti ProART. Anything above 120Hz, tells the GPU/software to turn off the third panel, even if you are on HDMI.

DDU'd, manually reinstalled with the latest drivers, changed cables, changed ports but the only thing that worked was manually setting all panels to 120Hz. Nvidia also says that you're able to run 4 displays with all panels at 120Hz.

4 - Multi Monitor:

• 4 independent displays at 4K 120Hz using DP or HDMI
• 2 independent displays at 4K 240Hz or 8K 60Hz with DSC using DP or HDMI
• Other display configurations may be possible based on available bandwidth

^ from here.

 

[robww]

I had a similar issue with my G7s running 3x4K. I had to turn Game Mode off on the monitors. With it set on, the Nvidia card would only allow 2 DPs to be connected. Effectively what Lutfij said, since I believe Game Mode sets the monitor to 144hz, and turning it off limits it to 120hz; although you're not running 3x4K, so you should be able to run at a higher refresh rate.