Arch Linux

pablodicosta

Member

Registered: 2024-04-07

Posts: 3

Low framerate in laptop with nVidia GPU and secondary monitor

I have a gaming laptop with a secondary monitor connected through HDMI and I'm experiencing low framerates while playing with Steam games.
Despite having configured everything apparently right and seeing good FPS in MangoHud, the actual framerate is at least half. This also seems to affect the compositor animations.
The curious thing is that everything works fine in the laptop monitor. Also, the problem doesn't exist when I use X11, it only happens in Wayland.
Enabling Adaptive Sync in my monitor improved the situation but still is far worse than X11

My software specs:
- ArchLinux 6.6.25-1-lts
- KDE Plasma 6
- nVidia proprietary drivers 550.67-4

My hardware specs:
- Laptop MSI Pulse GL66 (i7 11800H, 32 GB RAM)
- GeForce RTX3070 Max-Q
- Integrated monitor 1920x1080 @ 144hz
- Secondary monitor MSI Optix 3440x1440 @ 100hz

I've done a lot of research and tried several proposed solutions but still I couldn't fix this issue so I reach out to you in case you have any idea or similar experience.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 21,831

Re: Low framerate in laptop with nVidia GPU and secondary monitor

Wayland integration of PRIME functionality is generally very much in flux and likely somewhat normal currently. That everything works fine on the laptop monitor is normal, seeing as that doesn't actually need your nvidia gpu to render the desktop.

FWIW generally speaking for nvidia wayland anything to work correctly KMS needs to be enabled, is that the case? https://wiki.archlinux.org/title/NVIDIA … de_setting

Last edited by V1del (2024-04-08 14:36:32)

pablodicosta

Member

Registered: 2024-04-07

Posts: 3

Re: Low framerate in laptop with nVidia GPU and secondary monitor

Wayland integration of PRIME functionality is generally very much in flux and likely somewhat normal currently. That everything works fine on the laptop monitor is normal, seeing as that doesn't actually need your nvidia gpu to render the desktop.

FWIW generally speaking for nvidia wayland anything to work correctly KMS needs to be enabled, is that the case? https://wiki.archlinux.org/title/NVIDIA … de_setting

Sorry for the late reply. Indeed KMS is enabled. The issue is only happening in the secondary monitor connected via HDMI. There seems to be something that limits the framerate after it was rendered by the GPU, but at the same time the monitor gets a 100Hz signal. Maybe some kind of VSync?

Lone_Wolf

Forum Moderator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 11,972

Re: Low framerate in laptop with nVidia GPU and secondary monitor

The cable could be the limiting factor .

https://en.wikipedia.org/wiki/HDMI#Refr … esolutions indicates that 3440x1440 100 Hz needs 15.8 Gbit bandwidth or more .

A "Premium High Speed HDMI Cable" will barely be able to provide that, while the 'Ultra High Speed HDMI Cable' aka 48G aka category 3 HDMI cable should easily make it.

What cable are you using ?

---

Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

(A works at time B)  && (time C > time B ) ≠  (A works at time C)

seth

Member

Registered: 2012-09-03

Posts: 51,842

Re: Low framerate in laptop with nVidia GPU and secondary monitor

the problem doesn't exist when I use X11, it only happens in Wayland

Afaiu the OP 100Hz is expected and received by the output but the source doesn't look™ like its rendering at that pace.

seeing good FPS in MangoHud, the actual guesstimated framerate is at least half

Probably VRR or prime-sync related, @pablodicosta, do you get the same w/ eg. sway?

---

How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

pablodicosta

Member

Registered: 2024-04-07

Posts: 3

Re: Low framerate in laptop with nVidia GPU and secondary monitor

What cable are you using ?

It's a good quality cable, since I don't have the problem in X11 or Windows.

Probably VRR or prime-sync related, @pablodicosta, do you get the same w/ eg. sway?

I think the same. If I disable VRR in the monitor, the framerate reported by MangoHud and Steam goes down to an average of 50 FPS. When I turn VRR on, the reported framerate goes to 100 FPS but the actual video doesn't improve.
I had no success disabling PRIME Synchronization, maybe it's also related. I will try Sway or Hyperland in the following days.