4k Monitor suck at 30hz

Help
1

Hello I have recently brought a ASUS ROG PG27A monitor and it is stuck at 30hz, on the login screen it shows that it does 60hz, so something isn’t right, if I bump it down to 1980x1080 it does 60hz but in theory I should be able to do 60hz in 3680x2160. I am using this HDMI cable Pudney Ultra High Speed 8K HDMI 2.1 Cable (1m) - JB Hi-Fi NZ and have a NVIDIA GeForce GTX 1650. I am using a IdeaPad Gaming 3 15IHU6 laptop as well. My KDE Version is 6.4.3, My Frameworks version is 6.16.0, my QT version is 6.9.1, my kernal version is 6.15.8-arch1-2 (64-bit) and my distro is Arch Linux. I also brought this Displayport cable CABCXT10301/Cruxtec-DisplayPort-14-to-HDMI-21-Cable—2m—8K6 but the system wasn’t able to recognise it.

I wonder if this is a hardware problem or a KDE problem, any help with figuring out the problem would be greatly appreciated. Apologies if this is in the wrong forum.

2

I don’t have a 4K monitor but I can say that my monitor is a LG 27LS75Q-B (27 inches and running at 2560x1440) and I have 180Hz working with a GTX 1070. My cable is DP 1.4 to DP 1.4 (I don’t like mixes of technologies).

Fault of the graphics card, I think that not. I’ll shot to cable mix or soft.

Regards

3

In SDDM (the log in screen) I have 48Hz. Is when I start Plasma when the monitor raise to 180hz + HDR.

Regards

4

The kscreen-doctor -o command will list the modes available on your setup.

What does it report?

1 Like
5

kscreen-doctor -o

Modes: 1:2560x1440@180*! 2:2560x1440@165 3:2560x1440@144 4:2560x1440@120 5:2560x1440@100
6:2560x1440@60 7:1920x1080@120 8:1920x1080@100 9:1920x1080@60 10:1920x1080@60 11:1920x1080@50 1
2:1280x720@60 13:1280x720@50 14:1024x768@60 15:800x600@60 16:720x480@60 17:640x480@60 18:640x480
@60

This remembers me one thing. You can select the size of screen of Grub and SDDM with the settings of bootloader:

imagen
imagen2551×1064 309 KB

In my case, I have selected for consoles of boot (SDDM included) 1280x1024, the mode 13 (selected by graphics card) in the above command.

As @barryascott says, you need to see the messages of your kscreen-doctor -o. But first, the most important, see your resolution for bootloader (my screenshot is from Yast2 of openSUSE TW).

When you know the resolution for bootloader, type kscreen-doctor -o and search the resolution and the Hz that you have in SDDM.

I know that I have 1280x1024. If I see my command only can be mode 12 or 13. As my monitor marks 48hz is mode 13. If was 60hz would be mode 12.

Regards

6

For just SDDM you should be able to export your plasma monitor settings to SDDM via the settings “apply Plasma-settings…” (or something along this line as my system is not set to English) on top of the SDDM settings page in KDE.

That way SDDM should use the exact same mode as KDE, at least for me that way my Monitor even switches to HDR 120Hz at the SDDM screen. But not sure if that works with X11, or if you use KDE on wayland and SDDM is not set up correctly to use wayland as well, though. For HDR for sure both have to use wayland.

Unfortunately I also have no 4k Monitor only two external, HDMI and DP, and one internal all 2k Monitors but no problem setting all to the maximum refresh rates with my 4070M using up to date Arch.

7 
Output: 1 eDP-1 b8d6ffb8-4d53-4094-8e81-d29aa5c02c0e
        enabled
        connected
        priority 2
        Panel
        replication source:0
        Modes:  1:1920x1080@120*!  2:1280x1024@60  3:1280x1024@120  4:1024x768@60  5:1024x768@120  6:1280x800@60  7:1280x800@120  8:1920x1080@60  9:1600x900@60  10:1600x900@120  11:1368x768@60  12:1368x768@120  13:1280x720@60  14:1280x720@120 
        Geometry: 0,0 1920x1080
        Scale: 1
        Rotation: 1
        Overscan: 0
        Vrr: incapable
        RgbRange: Automatic
        HDR: incapable
        Wide Color Gamut: incapable
        ICC profile: none
        Color profile source: sRGB
        Color power preference: prefer efficiency and performance
        Brightness control: supported, set to 100% and dimming to 100%
        Color resolution: automatic (10), range: [6; 12] bits per color
        Allow EDR: always
Output: 2 HDMI-A-1 9cc5d569-fa91-468d-aeb3-53ee890406b9
        enabled
        connected
        priority 1
        HDMI
        replication source:0
        Modes:  15:1920x1080@60!  16:3840x2160@30*  17:3840x2160@30  18:3840x2160@24  19:3840x2160@24  20:1920x1080@60  21:1920x1080@60  22:1920x1080@50  23:1280x720@60  24:1280x720@60  25:1280x720@50  26:1024x768@60  27:800x600@60  28:720x576@50  29:720x480@60  30:720x480@60  31:640x480@60  32:640x480@60  33:640x480@60 
        Geometry: 1920,0 1920x1080
        Scale: 2
        Rotation: 1
        Overscan: 0
        Vrr: incapable
        RgbRange: Automatic
        HDR: incapable
        Wide Color Gamut: incapable
        ICC profile: none
        Color profile source: EDID
        Color power preference: prefer efficiency and performance
        Brightness control: supported, set to 100% and dimming to 100%
        DDC/CI: disallowed
        Color resolution: automatic (10), range: [8; 12] bits per color
        Allow EDR: unsupported

Newbie question but how do I do that

8

Here is a screenshot with the workflow:

image
image1339×692 162 KB

You need to apply all settings to SDDM every time you change the resolution, refresh rate or display arrangement of Plasma.

2 Likes
9

If you read this https://dlcdnta.asus.com/pub/ASUS/LCD%20Monitors/PG27AQ_English_V1.pdf?model=PG27AQ&Signature=HkIjioTYxOdu0CjG9O1ahr9Kpt-wI8gTmr9Gbcw4-fjeb0xiOU7Za-PiEb62GXosudJBLvzYp9J\\\~LJLKrxSOl9MxK3diVd0WEWFP-w7UemCNxyGPWu0lV5fv4fYpkcPlBkTeWjQS\\\~04UR3WXc2FVK0UtnRHesRe2t\\\~kGmryAfQUJnLW4mkwokDiQSr2fNkiZveG9jl3DtlnZOu-CSIuZGhiEi42aMiPB2rhNwSpoQV9dgHZdVgREFVpdhPN3BNd75MH6BFZAKnA5Vqz7u2MHx5eIBHminddo9ySQcF7EZkLXgi4iMT3X9e3Gn29fySYJkzGv\\\~HGRgehc1Wuc092BkQ\_\\\_&Expires=1754298151&Key-Pair-Id=K2ITB7O97XKKCX Section 3.2

It says that 3840x2160@60 only works on the DP connector, not HDMI.

Which matches what kscreen-doctor reported.

1 Like
10

Ok thanks for letting me know that seems to be the root of the problem, now my HDMI to displayport cable isn’t working should I make a new thread figuring why the cable isn’t getting detected by the system. Said cable has been tested on a friend’s setup and is working so the cable isn’t the problem

11

The cable must be DP at both ends. If you go from DP to HDMI then the monitor will treat the cable as a HDMI cable. If you do not have a DP connector on the computer end then there is nothing you can do.

1 Like
12

Ok thanks for letting me know, since my laptop doesn’t have a Displayport port if I buy a Displayport to Displayport cable then a Displayport to HDMI converter would that work?

13

If I had to guess, that is probably the wrong direction and the reason why the cable you mentioned was not recognised.

HDMI to Displayport seems not so commonly available, a short search just found one within dozens for the other direction. If it is “chinesium” enough to hide the fact the real source is HDMI it may work, but I would not guarantee it (and for that reason will not provide a link, sorry.)

1 Like
14

That is the same as HDMI to DP, the cables as passive, so no that will not work.

The HDMI port in the laptop is the limit not the cables.

15

The one I found needed a additional USB “for optimal performance” but I would rather think to power a circuit:

image
image260×200 21.6 KB

Would not consider that passive, but have not tried either.

16

You need to check that the HDMI port on your laptop can output 3840x2160@60.

My guess is it cannot output @60.

17

The NVIDIA GeForce GTX 1650 and the IdeaPad Gaming 3 15IHU6 listings say HDMI 2.0, with that it theoretically should.
Some of the IdeaPad Gaming 3 15IHU6 variants list a GTX 1650 with 8GB other with 4GB. The 8GB Models should be able to output 4k@60Hz outside of games at least, within games the FPS will probably drop instantly.
With only 4GB especially if the card has also to drive the internal IdeaPad display at the same time you are maybe right and it can not handle 4k@60Hz at all.