XFCE(x11) sluggish under GPU or CPU load.

runzilla · 2026-01-29 14:49:21

Hello!
I recently upgraded my PC.

Specs:

- Arch Linux Hardened 6.17.13
- AMD Radeon RX 6800 XT
- AMD Ryzen 5950X
- 32GB RAM CL14
- 9100 Pro NVMe

Problem:
Now I’m experiencing severe lags and stutters under GPU load. CPU load standalone also seems to perform poorly.

gpu:
- When running OCCT (GPU) or Hashcat, XFCE becomes sluggish and laggy.
- With Mesa drivers, after a few seconds it sometimes crashes back to LightDM.
- With AMDGPU-PRO, it doesn’t log out, but the system is still practically unusable.

for cpu:
Running CPU tests in OCCT shows similar issues. It’s slightly more usable than GPU stress, but typing is delayed — each key appears with about a one-second lag.

Comparison:

- On Windows 11, the same hardware had no issues. Cinebench and FurMark could run simultaneously while I was still able to browse the system smoothly.
- My previous Arch build (Ryzen 2600 + 5700 XT) handled Hashcat, three VMs, and a browser at the same time without any stutters.

What I’ve tried:

- AMDGPU-PRO and Mesa drivers
- Running Hashcat inside a TTY and switching back to XFCE — the same issues persist

sudo journalctl -b | curl -F 'file=@-' 0x0.st
https://0x0.st/PNF0.txt

dmesg | grep -i amdgpu / lspci -k | grep -A 3 -i vga / glxinfo | grep -i "renderer\|version"
https://pastebin.com/cDQDpBEy

ToZ · 2026-01-29 18:08:31

Hello and welcome.

I recently upgraded my PC.

Was this a hardware-only upgrade or did you re-install the O/S as well?

My previous Arch build (Ryzen 2600 + 5700 XT) handled Hashcat, three VMs, and a browser at the same time without any stutters.

Was this also under Xfce?

Running Hashcat inside a TTY and switching back to XFCE — the same issues persist

When you say TTY, do you mean a terminal within Xfce or did you Ctrl-Alt-Fx? (not familiar with hashcat)

A couple of suggestions:

Disable compositing on Xfce via Settings Manager > Window Manager Tweaks > Compositing tab. If this makes a difference, then the compositor is most likely the culprit.
I notice that you are using the kernel parameters "pti=on page_alloc.shuffle=1" (security mitigations)? These are known to introduce performance issues (of varying intensity depending on system). Could you try booting without them to see if there is improvement?

I'll do a deeper dive through your log files later tonight.

runzilla · 2026-01-29 20:01:18

Thank you for your response!!
I’m a bit of a Linux rookie (first year), so sorry if I miss anything.

I made a hardware upgrade and decided not to reinstall the whole system smile
I just rsynced it to the new SSD and installed GRUB on it.

Regarding TTY — I was still on XFCE when using the shortcut:
I pressed `Ctrl + Alt + F3`, ran the hashcat command there, and then switched back to XFCE via `Ctrl + Alt + F6`.

1. I tried running w/o the compositor. no luck sad

2. Kernel parameters `pti=on page_alloc.shuffle=1` — I believe the system set it automatically.
It seems like it might be related to the CPU, so I’ll try disabling that parameter and testing irqbalance tweak as well.

- XFCE + AMDGPU-PRO (no crash): https://pastebin.com/PE5inwVU
- Hashcat + OCCT + Mesa + xf86-video-amdgpu (no crash this time): https://pastebin.com/c4F2hgBE

UPDATE: tried pti=off page_alloc.shuffle=0 in GRUB, it didn’t affect system performance.
I also uploaded a video that shows how badly it performs - https://youtu.be/ERtZpWxaE3I
6.12.67-1-lts with deleted xf86-video packages didn’t make any difference, unfortunately.

Last edited by runzilla (2026-01-29 20:53:08)

ToZ · 2026-01-30 00:34:50

Have a look through this thread and try the different vblank settings: off, glx, and xpresent. Note that with xpresent, you need the "libxpresent" library installed (its in the repo). Test using the xfconf-query command and see if any make a difference.

runzilla · 2026-01-30 00:46:31

glx, xpresent and off - looks the same to me.
Those lags remind me situation when you're out of ram and running clearly on swap. And they are really brutal lags to be fair, it's literally non usable

tried:
stress-ng --cpu 0 --cpu-method all --verify --timeout 10m
stress-ng --vm 4 --vm-method all --vm-bytes 28G --timeout 15m --verify
works like a charm. cpu is 100% but no lags whatsoever

but OCCT ( cpu+ram, cpu, linpack, memory ) makes it sluggish. and if i add 3d adaptive + vram = slideshow

Last edited by runzilla (2026-01-30 01:09:30)

ToZ · 2026-01-30 01:06:12

This is starting to look like a driver issue then. Have a read through this thread - there are some suggestions there that you could try.

runzilla · 2026-01-30 01:20:44

Yeah, seems like driver issues to me as well, but i tried 2 types of amd drivers and still no changes

tried those setting from post

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash \
amdgpu.noretry=0 amdgpu.lockup_timeout=0 amdgpu.gpu_recovery=1 \
amdgpu.runpm=0 amdgpu.mcbp=0 amdgpu.dcdebugmask=0x600 \
amdgpu.ppfeaturemask=0xf7fff"

after reboot checked that those settings applied correctly via
cat /sys/module/amdgpu/parameters/runpm

Lags still persists sad

also someone told me that i might have transferred /tmp and /run with rsync. actually i don't remember and i think that i excluded those paths

Update: installed new xfce arch on spare disk - same issue. It's 100% opencl/ROCm related thing. i tried POCL (that rely on CPU and it works)
Probably card is not supported for some odd reason

Last edited by runzilla (2026-01-30 21:33:41)

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#1 2026-01-29 14:49:21

XFCE(x11) sluggish under GPU or CPU load.

#2 2026-01-29 18:08:31

Re: XFCE(x11) sluggish under GPU or CPU load.

#3 2026-01-29 20:01:18

Re: XFCE(x11) sluggish under GPU or CPU load.

#4 2026-01-30 00:34:50

Re: XFCE(x11) sluggish under GPU or CPU load.

#5 2026-01-30 00:46:31

Re: XFCE(x11) sluggish under GPU or CPU load.

#6 2026-01-30 01:06:12

Re: XFCE(x11) sluggish under GPU or CPU load.

#7 2026-01-30 01:20:44

Re: XFCE(x11) sluggish under GPU or CPU load.

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