I’m frequently using DaVinci Resolve Studio and Blender for various tasks (but not simultaneously). I have a decently powerful Nvidia RTX A4000 16GB GPU, yet in both of these programs have at various occasions hit out of memory errors, specifically VRAM memory (my system has 64GB RAM).
Today, I decided to do a little digging into this, because on one Blender project, the numbers just weren’t adding up, with it failing out at a mere fraction of my total VRAM.
A quick search and I read about the nvidia-smi tool, which gives you a nice printout of current VRAM usage and the associated processes, for Nvidia users.
nvidia-smi
What I discovered was /usr/bin/plasmashell was consuming 12GB of VRAM! The amount of times over recent years I have hit VRAM limits, and to think all this time it was probably just Plasma chewing up ¾ of it
I changed Plasma’s Rendering Backend from “Automatic”, to “Software” and rebooted and bam, I now have loads of VRAM available for actual work. Plasma warns me that “Rendering may be degraded” because it’s in Software mode, but I’ve yet to see a difference.
Based on that thread, it looks like it might be web browsers chewing up the VRAM (albeit via /usr/bin/plasmashell if that’s the case). I am running dual display with one being a 4K, which that thread suggests is a factor too:
2750 x 1440 (1440p)
3840 x 2160 (4K)
I might switch back to “Automatic” rendering backend and run a few more tests. I’m referencing dozens of browser tabs at a time for what I’m working on in Blender.
This issue seems to at least be in part due to slideshow wallpapers. Everytime the wallpaper cycles, additional VRAM is consumed by plasmashell. Even after halving the wallpaper update frequency on both displays from 1 minute, to 2 minutes, plasmashell is still consuming a whopping 12GB of VRAM after just 4 hours. Nothing is freed up by closing all desktop applications.
Below is nvidia-smi’s output after 4:14 hours of uptime. Note plasmashell’s 12120MiB of usage:
+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 575.64.05 Driver Version: 575.64.05 CUDA Version: 12.9 |
|-----------------------------------------+------------------------+----------------------+
| GPU Name Persistence-M | Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap | Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|=========================================+========================+======================|
| 0 NVIDIA RTX A4000 Off | 00000000:09:00.0 On | 0 |
| 41% 51C P5 21W / 140W | 12864MiB / 15352MiB | 0% Default |
| | | N/A |
+-----------------------------------------+------------------------+----------------------+
+-----------------------------------------------------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=========================================================================================|
| 0 N/A N/A 1874 G /usr/bin/ksecretd 3MiB |
| 0 N/A N/A 1914 G /usr/bin/kwin_wayland 205MiB |
| 0 N/A N/A 2001 G /usr/bin/Xwayland 3MiB |
| 0 N/A N/A 2037 G /usr/bin/ksmserver 3MiB |
| 0 N/A N/A 2039 G /usr/bin/kded6 3MiB |
| 0 N/A N/A 2055 G /usr/bin/plasmashell 12120MiB |
| 0 N/A N/A 2098 G /usr/bin/kaccess 3MiB |
| 0 N/A N/A 2100 G ...it-kde-authentication-agent-1 3MiB |
| 0 N/A N/A 2201 G /usr/bin/kdeconnectd 3MiB |
| 0 N/A N/A 2265 G /usr/bin/xwaylandvideobridge 3MiB |
| 0 N/A N/A 2302 G /usr/lib/xdg-desktop-portal-kde 3MiB |
| 0 N/A N/A 2574 G /usr/bin/kwalletd6 3MiB |
| 0 N/A N/A 7769 G /usr/lib/baloorunner 3MiB |
| 0 N/A N/A 99697 G /usr/bin/krunner 7MiB |
| 0 N/A N/A 106314 G /usr/bin/konsole 3MiB |
+-----------------------------------------------------------------------------------------+
12:52:38 up 4:14, 1 user, load average: 0.15, 0.20, 0.18
Other issues start to present at this point, with LibreWolf becoming visually glitchy too.
Running this command frees up the VRAM and seems to fix LibreWolf’s issues too (after restarting LibreWolf):
plasmashell --replace &
+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 575.64.05 Driver Version: 575.64.05 CUDA Version: 12.9 |
|-----------------------------------------+------------------------+----------------------+
| GPU Name Persistence-M | Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap | Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|=========================================+========================+======================|
| 0 NVIDIA RTX A4000 Off | 00000000:09:00.0 On | 0 |
| 41% 51C P5 22W / 140W | 1227MiB / 15352MiB | 0% Default |
| | | N/A |
+-----------------------------------------+------------------------+----------------------+
+-----------------------------------------------------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=========================================================================================|
| 0 N/A N/A 1874 G /usr/bin/ksecretd 3MiB |
| 0 N/A N/A 1914 G /usr/bin/kwin_wayland 223MiB |
| 0 N/A N/A 2001 G /usr/bin/Xwayland 4MiB |
| 0 N/A N/A 2037 G /usr/bin/ksmserver 3MiB |
| 0 N/A N/A 2039 G /usr/bin/kded6 3MiB |
| 0 N/A N/A 2098 G /usr/bin/kaccess 3MiB |
| 0 N/A N/A 2100 G ...it-kde-authentication-agent-1 3MiB |
| 0 N/A N/A 2201 G /usr/bin/kdeconnectd 3MiB |
| 0 N/A N/A 2265 G /usr/bin/xwaylandvideobridge 3MiB |
| 0 N/A N/A 2302 G /usr/lib/xdg-desktop-portal-kde 3MiB |
| 0 N/A N/A 2574 G /usr/bin/kwalletd6 3MiB |
| 0 N/A N/A 7769 G /usr/lib/baloorunner 3MiB |
| 0 N/A N/A 99697 G /usr/bin/krunner 7MiB |
| 0 N/A N/A 106314 G /usr/bin/konsole 3MiB |
| 0 N/A N/A 106484 G ...latform=wayland --disable-gpu 3MiB |
| 0 N/A N/A 107640 G plasmashell 474MiB |
+-----------------------------------------------------------------------------------------+
The amount of times over recent years I have hit VRAM limits, and to think all this time it was probably just Plasma chewing up ¾ of it 
