I am running Debian testing on a FW 13-AMD 7840U, with a stock kernel, 6.10.9-amd64, using PPD 0.23 from Debian testing. I was getting pretty decent battery life from it (between 5 and 10 Watts under a modest load). I got excited by the arrival of the 2.8K display and installed it on this machine and power consumption is consistently above 12 Watts, sometimes as high as 18, under the same loads I had before. Is this to be expected? It makes my battery last somewhere around 4 hours which I find too low. I am thinking of replacing the new display with the original one, partly because I don’t see enough of a difference between the two displays to sacrifice that much battery life.
Have you turned on VRR? This should help.
Didn’t think we had VRR on Linux. I’ve been running 60hz for battery life.
Hank, it’s pushing more pixels and at double the refresh rate. I don’t think the big jump in discharge is the difference in screen. Check what discharge rate you get when you set 60hz and something close to the original resolution?
Sorry for the dumb question: How do I turn on VRR? I am using GNOME/Wayland.
Thanks. Hank
I discovered I had an open Firefox tab that was eating a lot of CPU cycles. Closing that brought me down a watt or so. Turning the refresh rate to 60Hz brought the discharge rate down another 2 watts. I’m back to close to 6 Watts, which I can live with. I will also try dropping the resolution at some point, too. Thanks for the suggestion.
It’s an experimental option in GNOME. Look it up. Kde it’s front and center in display settings by default.
I was thinking just to get a baseline of the difference between new and old panel.
Thanks for the tip, I found it and am trying it now: Variable refresh rate from 30 to 120 Hz.
I’m trying Mario’s suggestion for VRR. I’ll try yours next if that doesn’t help. Setting it to 60Hz definitely made a difference, tho, even without lowering the resolution.
Can you common on how much ‘a difference’ is? Debating getting this panel!
I can get the power usage down to around 6W by setting VRR to a max of 60Hz, while keeping the higher resolution. I tried dropping the resolution and didn’t see much difference. I’m still not convinced I have all the power settings right for this machine, though - power usage occasionally gets to 5W but mostly is higher, generally 6 to 7, sometimes spikes up at 14W if I’m spinning up a VM.
Wow. I will probably upgrade then! Looks like Sway also supports VRR. Thank you for the update.
I was getting ~10w idle with all my usual apps open, with refresh at 120Hz, enabled VRR on Gnome down to ~6w.
I would say that the display itself is not the one giving more power draw but it’s the iGPU.
I’m running Fedora 40 with the latest kernel.