I have noticed that on a fresh Fedora 41 KDE Plasma Spin Live USB, after a few minutes it settles down to an idle power of around 6W, assumingly because the NVIDIA card is not being used in favour of the iGPU, and even works great with an external monitor connected.
On my existing Fedora install (which I switched recently from Gnome to Plasma), which has the latest nvidia propietary drivers installed, I’m idling at ~15W.
Does someone know what configuration my install might have that increases the power usage? I haven’t down much else to the GPU config than installing the proprietary drivers and installing (and recently uninstalling and resetting before) envycontrol.
There was a thing with GPUs newer than Maxwell where they can’t clock-up to their highest frequency, but would be fine with open-source nouveau drivers for low-performance 3D like the desktop. Not having access to the high-performing clocks would have lower power-usage.
Installing the proprietary driver allows the higher-frequencies and likely higher or different 3D usage (more GL/VK features available = more stuff possibly using them = more power vs nouveau).
The live boot uses the nouveau driver and cannot use 3d or hardware acceleration on the gpu.
It will always use a little less power than the proprietary drivers.
How are you comparing the power usage of the dGPU?
With the nvidia driver you can use the nvidia-smi command to see the power used, but with nouveau that is not possible.
I’m comparing power usage using powertop + btop, but I’ve also had look at nvidia-smi which just shows no processes running and 11W idle consumption.
it seems to me as nouveau (by default) allows the GPU to enter a low-power state and let the iGPU do it’s thing if the dGPU was completely off/not recognised the display output would not be working as it’s tied to the dGPU on my laptop. Is it possible to do this with the propietary drivers as well? I’ve tried enabling dynamic power management, but it doesn’t seem to have had any effect.
Nouveau doesn’t take full advantage of the dGPU, but is adequate for many purposes and does use less power, so is often preferred over Nvidia drivers when laptop runtime on battery is a concern. It is possible to have the Nvidia drivers installed and switch to nouveau when you need to extend runtime on the battery (see the Nvidia rpmfusion howto).
