I noticed that my monitor (seat1) is displayed at 30Hz while the monitor of seat2 is displayed at 60Hz. And that although the graphics card for my monitor is much newer.
After some back and forth with monitor inputs and graphics card outputs and cables, I then could set my monitor to 60 Hz. But when I checked the second monitor, it no longer had a picture. (although nothing has been changed on his graphics card, cable and monitor.)
After further attempts it turns out that exactly one of the two monitors can be set to 60Hz. If both are set to 60 Hz, the image on one monitor disappears and only reappears when one is set to 30 Hz again.
This is independent of whether I am working in the dual monitor (single seat) or in the multiseat mode.
Is it possible to change this ?
sudo inxi -Fazy
System:
Kernel: 5.14.10-1-MANJARO x86_64 bits: 64 compiler: gcc v: 11.1.0
parameters: BOOT_IMAGE=/@/boot/vmlinuz-5.14-x86_64
root=UUID=3487ba3d-1cba-4cdc-a043-c420ebca2aca rw rootflags=subvol=@
bootsplash.bootfile=bootsplash-themes/manjaro/bootsplash
modprobe.blacklist=ccp udev.log_priority=3 audit=0 sysrq_always_enabled=1
Desktop: Xfce 4.16.0 tk: Gtk 3.24.29 info: xfce4-panel wm: xfwm 4.16.1
dm: LightDM 1.30.0 Distro: Manjaro Linux base: Arch Linux
Machine:
Type: Desktop Mobo: ASRock model: B450 Pro4 serial: <filter>
UEFI: American Megatrends v: P1.10 date: 06/19/2018
Battery:
Device-1: hidpp_battery_0 model: Logitech Wireless Keyboard K270
serial: <filter> charge: 55% (should be ignored) rechargeable: yes
status: Discharging
Device-2: hidpp_battery_1 model: Logitech K520 serial: <filter>
charge: 50% (should be ignored) rechargeable: yes status: N/A
Device-3: hidpp_battery_2 model: Logitech M310 serial: <filter>
charge: 55% (should be ignored) rechargeable: yes status: Discharging
CPU:
Info: 8-Core model: AMD Ryzen 7 2700 socket: AM4 bits: 64 type: MT MCP
arch: Zen+ family: 17 (23) model-id: 8 stepping: 2 microcode: 800820D cache:
L1: 768 KiB L2: 4 MiB L3: 16 MiB
flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm
bogomips: 102232
Speed: 1486 MHz min/max: 1550/3200 MHz base/boost: 3200/4100 boost: enabled
volts: 1.0 V ext-clock: 100 MHz Core speeds (MHz): 1: 1486 2: 1520 3: 1378
4: 1376 5: 1375 6: 1339 7: 1424 8: 1379 9: 1377 10: 1377 11: 1375 12: 1376
13: 1547 14: 1545 15: 1378 16: 1378
Vulnerabilities: Type: itlb_multihit status: Not affected
Type: l1tf status: Not affected
Type: mds status: Not affected
Type: meltdown status: Not affected
Type: spec_store_bypass
mitigation: Speculative Store Bypass disabled via prctl and seccomp
Type: spectre_v1
mitigation: usercopy/swapgs barriers and __user pointer sanitization
Type: spectre_v2 mitigation: Full AMD retpoline, IBPB: conditional, STIBP:
disabled, RSB filling
Type: srbds status: Not affected
Type: tsx_async_abort status: Not affected
Graphics:
Device-1: NVIDIA GK107 [GeForce GT 740] vendor: eVga.com. driver: nouveau
v: kernel bus-ID: 01:00.0 chip-ID: 10de:0fc8 class-ID: 0300
Device-2: NVIDIA GP107 [GeForce GTX 1050 Ti] vendor: Gigabyte
driver: nouveau v: kernel bus-ID: 27:00.0 chip-ID: 10de:1c82 class-ID: 0300
Device-3: Logitech C922 Pro Stream Webcam type: USB
driver: snd-usb-audio,uvcvideo bus-ID: 1-6.1:5 chip-ID: 046d:085c
class-ID: 0102 serial: <filter>
Display: server: X.org 1.20.13 compositor: xfwm4 v: 4.16.1 driver:
loaded: modesetting alternate: fbdev,vesa resolution: <missing: xdpyinfo>
OpenGL: renderer: NV137 v: 4.3 Mesa 21.2.3 direct render: Yes
Audio:
Device-1: NVIDIA GK107 HDMI Audio vendor: eVga.com. driver: snd_hda_intel
v: kernel bus-ID: 01:00.1 chip-ID: 10de:0e1b class-ID: 0403
Device-2: NVIDIA GP107GL High Definition Audio vendor: Gigabyte
driver: snd_hda_intel v: kernel bus-ID: 27:00.1 chip-ID: 10de:0fb9
class-ID: 0403
Device-3: AMD Family 17h HD Audio vendor: ASRock driver: snd_hda_intel
v: kernel bus-ID: 29:00.3 chip-ID: 1022:1457 class-ID: 0403
Device-4: Logitech C922 Pro Stream Webcam type: USB
driver: snd-usb-audio,uvcvideo bus-ID: 1-6.1:5 chip-ID: 046d:085c
class-ID: 0102 serial: <filter>
Sound Server-1: ALSA v: k5.14.10-1-MANJARO running: yes
Sound Server-2: JACK v: 1.9.19 running: no
Sound Server-3: PulseAudio v: 15.0 running: no
Sound Server-4: PipeWire v: 0.3.38 running: yes
Network:
Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet
vendor: ASRock driver: r8169 v: kernel port: c000 bus-ID: 25:00.0
chip-ID: 10ec:8168 class-ID: 0200
IF: enp37s0 state: up speed: 1000 Mbps duplex: full mac: <filter>
Bluetooth:
Device-1: Cambridge Silicon Radio Bluetooth Dongle (HCI mode) type: USB
driver: btusb v: 0.8 bus-ID: 1-6.2:9 chip-ID: 0a12:0001 class-ID: e001
Report: bt-adapter ID: hci0 rfk-id: 0 state: up address: <filter>
Drives:
Local Storage: total: 3.37 TiB used: 417.41 GiB (12.1%)
ID-1: /dev/nvme0n1 maj-min: 259:0 vendor: A-Data model: SX8200PNP
size: 1.86 TiB block-size: physical: 512 B logical: 512 B speed: 31.6 Gb/s
lanes: 4 type: SSD serial: <filter> rev: 42AZS6AC temp: 37.9 C scheme: GPT
SMART: yes health: PASSED on: 138d 7h cycles: 213
read-units: 2,456,511 [1.25 TB] written-units: 11,161,929 [5.71 TB]
ID-2: /dev/sda maj-min: 8:0 vendor: SanDisk model: SDSSDH31000G
family: Marvell based SSDs size: 931.51 GiB block-size: physical: 512 B
logical: 512 B sata: 3.3 speed: 6.0 Gb/s type: SSD serial: <filter>
rev: 10RL temp: 32 C scheme: GPT
SMART: yes state: enabled health: PASSED on: 1y 292d 22h cycles: 1077
ID-3: /dev/sdb maj-min: 8:16 vendor: A-Data model: SP610 size: 476.94 GiB
block-size: physical: 512 B logical: 512 B sata: 3.1 speed: 6.0 Gb/s
type: SSD serial: <filter> rev: 2C temp: 33 C scheme: GPT
SMART: yes state: enabled health: PASSED on: 37d 18h cycles: 2774
read: 360.9 MiB written: 504.1 MiB Old-Age: UDMA CRC errors: 446
ID-4: /dev/sdc maj-min: 8:32 vendor: A-Data model: SX900 size: 119.24 GiB
block-size: physical: 512 B logical: 512 B sata: 3.0 speed: 6.0 Gb/s
type: SSD serial: <filter> rev: 7a temp: 37 C scheme: GPT
SMART: yes state: enabled health: PASSED on: 2y 266d 4h cycles: 2993
read: 4.2 MiB written: 2.3 MiB
ID-5: /dev/sdd maj-min: 8:48 type: USB vendor: A-Data model: USB Flash Drive
size: 14.73 GiB block-size: physical: 512 B logical: 512 B type: SSD
serial: <filter> rev: 1.00 scheme: GPT
SMART Message: Unknown USB bridge. Flash drive/Unsupported enclosure?
Partition:
ID-1: / raw-size: 900 GiB size: 900 GiB (100.00%) used: 417.4 GiB (46.4%)
fs: btrfs block-size: 4096 B dev: /dev/sda2 maj-min: 8:2
ID-2: /boot/efi raw-size: 953 MiB size: 951.1 MiB (99.80%)
used: 8.2 MiB (0.9%) fs: vfat block-size: 512 B dev: /dev/sda1 maj-min: 8:1
ID-3: /home raw-size: 900 GiB size: 900 GiB (100.00%)
used: 417.4 GiB (46.4%) fs: btrfs block-size: 4096 B dev: /dev/sda2
maj-min: 8:2
Swap:
Alert: No swap data was found.
Sensors:
System Temperatures: cpu: 37.5 C mobo: N/A
Fan Speeds (RPM): N/A
GPU: device: nouveau temp: 55.0 C fan: 0 device: nouveau temp: 37.0 C
mV: 975.00
Info:
Processes: 446 Uptime: 16m wakeups: 7 Memory: 46.99 GiB
used: 10.37 GiB (22.1%) Init: systemd v: 249 tool: systemctl Compilers:
gcc: 11.1.0 clang: 12.0.1 Packages: pacman: 2104 lib: 459 Shell: Zsh (sudo)
v: 5.8 running-in: xfce4-terminal inxi: 3.3.08
Hmm, could be the driver, or could be a hardware/bandwidth limitation. Are you driving higher resolutions? Are the cables identical, or might there be an HDMI/DP specification gap between them? For example, an HDMI 1.4 cable only has enough bandwidth to drive a 4K resolution at 30hz.
Looks like you have two GPU’s listed, are the HDMI/DP cables being fed from one GPU or split between the cards?
One monitor (4k/60Hz) is connected to card1. The other(4k/60Hz) is connected to card2.
I do configure with “Anwendungen”->“Einstellungen”->“Anzeige”
There it is possible to select 30Hz or 60Hz. This is selectable for each monitor.
- Monitor1 30Hz, Monitor2 30Hz - works
- Monitor1 30Hz, Monitor2 60Hz - works
- Monitor1 60Hz, Monitor2 30Hz - works
- Monitor1 60Hz, Monitor2 60Hz
When i press apply then Monitor2 goes black, and stays black until the timeout of the configuration-dialog resets the Monitor2 to 30Hz. After that the configuration is reverted and Monitor1 works again with 60Hz and Monitor2 with 30Hz 
When 60/60 doesn’t work… is it the monitor connected to the 740 that blanks? Are you using DVI or HDMI from that card? What’s confusing me now is that according to GeForce GT 740 | Specifications | GeForce * - 3840x2160 at 30Hz or 4096x2160 at 24Hz supported over HDMI… and if that’s true, how did 60hz ever work? Even DVI on the 740 can’t hit 4K/60 according to the DVI spec’s @ Digital Visual Interface - Wikipedia
What does xrandr report?
Are you able to connect both monitors to the 1050Ti? Not sure which model yours is… but the GeForce® GTX 1050 Ti D5 4G(rev1.0/rev1.1/rev1.2) Specification | Graphics Card - GIGABYTE Global card I looked at can definitely support 2x 4K monitors on it’s own using one DP and one HDMI connection (with the matching spec’d cables):
HDMI-2.0b*1 (Max Resolution: 4096x2160 @60 Hz)
Display Port-1.4 *1 (Max Resolution: 7680x4320 @60 Hz)
I would also have said, that 60Hz with the GT740 should not be possible. This is xrandr used on both seats while using multiseat-mode. (Monitor1 60Hz, Monitor2 30Hz - works)
Therefore i cant use both monitors at GTX 1050Ti. I need 2 seats with separate monitors/keyboards/mice. I could not get this running wit one card 
xrandr GT 740 = Monitor2
cat /tmp/xrandr.seat1.txt
Screen 0: minimum 320 x 200, current 3840 x 2160, maximum 16384 x 16384
DVI-I-1 disconnected (normal left inverted right x axis y axis)
DVI-D-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
3840x2160 59.97 30.00* 30.00 25.00 24.00 29.97 23.98
3200x1800 59.96 59.94
2880x1620 59.96 59.97
2560x1600 59.99 59.97
2560x1440 59.99 59.96 59.95
2048x1536 60.00
1920x1440 60.00
1856x1392 60.01
1792x1344 60.01
2048x1152 59.99 59.98 59.90 59.91
1920x1200 59.88 59.95
1920x1080 60.01 59.97 59.96 60.00 50.00 59.94 59.93 30.00 24.00 29.97 23.98
1600x1200 60.00
1680x1050 59.95 59.88
1400x1050 59.98
1600x900 59.99 59.94 59.95 60.00 59.82
1280x1024 60.02
1400x900 59.96 59.88
1280x960 60.00
1440x810 60.00 59.97
1368x768 59.88 59.85
1280x800 59.99 59.97 59.81 59.91
1280x720 60.00 59.99 59.86 60.00 59.94 59.74
1024x768 60.04 60.00
960x720 60.00
928x696 60.05
896x672 60.01
1024x576 59.95 59.96 59.90 59.82
960x600 59.93 60.00
960x540 59.96 59.99 59.63 59.82
800x600 60.00 60.32 56.25
840x525 60.01 59.88
864x486 59.92 59.57
720x576 50.00
700x525 59.98
800x450 59.95 59.82
720x480 60.00 59.94
640x512 60.02
700x450 59.96 59.88
640x480 60.00 60.00 59.94
720x405 59.51 58.99
684x384 59.88 59.85
640x400 59.88 59.98
640x360 59.86 59.83 59.84 59.32
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32 56.34
432x243 59.92 59.57
320x240 60.05
360x202 59.51 59.13
320x180 59.84 59.32
HDMI-1 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
3840x2160 59.97 30.00* 30.00 25.00 24.00 29.97 23.98
This monitor has OSD-info about resolution and frequency, and it says: Auflösung: 3840x2160/30Hz 
xrandr GTX1050Ti = Monitor1
cat /tmp/xrandr.seat0.txt
Screen 0: minimum 320 x 200, current 3840 x 2160, maximum 16384 x 16384
DVI-D-2 disconnected (normal left inverted right x axis y axis)
HDMI-2 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
3840x2160 60.00*+ 50.00 59.94 59.97 30.00 30.00 25.00 24.00 29.97 23.98
3200x1800 59.96 59.94
2880x1620 59.96 59.97
2560x1600 59.99 59.97
2560x1440 59.99 59.96 59.95
2048x1536 60.00
1920x1440 60.00
1856x1392 60.01
1792x1344 60.01
2048x1152 59.99 59.98 59.90 59.91
1920x1200 59.88 59.95
1920x1080 60.01 59.97 59.96 60.00 60.00 59.94 59.93 30.00 24.00 29.97 23.98
1600x1200 60.00
1680x1050 59.95 59.88
1400x1050 59.98
1600x900 59.99 59.94 59.95 60.00 59.82
1280x1024 60.02
1400x900 59.96 59.88
1280x960 60.00
1440x810 60.00 59.97
1368x768 59.88 59.85
1280x800 59.99 59.97 59.81 59.91
1280x720 60.00 59.99 59.86 60.00 59.94 59.74
1024x768 60.04 60.00
960x720 60.00
928x696 60.05
896x672 60.01
1024x576 59.95 59.96 59.90 59.82
960x600 59.93 60.00
960x540 59.96 59.99 59.63 59.82
800x600 60.00 60.32 56.25
840x525 60.01 59.88
864x486 59.92 59.57
700x525 59.98
800x450 59.95 59.82
720x480 60.00 59.94
640x512 60.02
700x450 59.96 59.88
640x480 60.00 60.00 59.94
720x405 59.51 58.99
684x384 59.88 59.85
640x400 59.88 59.98
640x360 59.86 59.83 59.84 59.32
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32 56.34
432x243 59.92 59.57
320x240 60.05
360x202 59.51 59.13
320x180 59.84 59.32
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-3 disconnected (normal left inverted right x axis y axis)
HDMI-4 disconnected (normal left inverted right x axis y axis)
HDMI-2 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
3840x2160 60.00*+ 50.00 59.94 59.97 30.00 30.00 25.00 24.00 29.97 23.98
This monitor has no OSD info about resolution and frequency
So I wonder if the issue is that the GUI settings tool is picking 60hz, when according to xrandr 59.97hz would be more correct?
Hmm, I’m not sure… as man xrandr points out that it will use the “nearest”… and it’s likely the settings tool is using xrandr behind the scenes.
--rate rate
This marks a preference for refresh rates close to the specified value, when multiple modes have the same name, this will select the one with the nearest refresh rate.
But what’s the definition of “nearest”? equal to or greater than, equal to or less than, or somewhere between the two? Wonder what would happen if you manually set the monitor to 59.97 with xrandr?
I wonder if this thread would help you, which basically suggests manual intervention… [SOLVED] Can't change refresh rate with xrandr / Multimedia and Games / Arch Linux Forums
xrandr --output HDMI-1 --mode 3840x2160 --rate 60
I’m also starting to think that it might be important to consider where xrandr is getting it’s information. for example, the link I provided earlier indicated that a 740 could only do 4K/30hz, but if (hypothetically) xrandr is only querying the monitor, it could be correct reporting the monitor supports 59.97hz… but success requires you have a video card that can drive it; which on paper the 740 does not.
And then what throws all this thinking out is your listed scenarios where HDMI-1 did achieve 60hz when HDMI-2 was set to 30hz 
P.S. Do either of your monitors support DP? If so, I’d be interested to see what happens with 2 monitors connected to the 1050Ti (DP + HDMI)… but I suspect the reason you are using 2 cards is because you needed two HDMI ports.
The reason is that i do need a multiseat setup. I do use loginctl to set one card belonging to seat1. The other belongs to seat0.
I had tried before to use only one card. But i never got it working with two seats. Also i changed to nouveau because it was way more stable in my setup then the nvidia-driver. And with loginctl i don’t have to use any xorg configfiles. This works automagic between lightdm, loginctl and xorg in xfce. I only have to setup loginctl for seat1.
And this handles not only graphics, but also sound, USB-Ports with keyboards, mice and USB-Sticks for seat1 
