I have reason to drive my laptops power use as far down as I possibly can in an ‘every watt matters’ kind of way, and I’ve spent a couple hours with a wattmeter doing what I can. As a baseline my laptop used about 60w give or take when just browsing or idling.
First thing i did was to boot into windows, which had about the same kind of power draw at a glance, i went to the power management settings and turned everything there to the maximum powersaving option, my powerdraw went real low in the same kind of testing scenario, it averaged about 25w, with spikes as low as 17w, but occasionally jumping to around 40w seemingly at random (just windows things I suppose)
This gave me an idea of how much powersaving there is to be had on my laptop.
First off I installed TLP
Just this halved my power consumption, when browsing or idling from ~60 to ~30. (Why isn’t this installed by default again? I remember it used to be)
I switched it to battery mode, it went to ~60 again, which is weird, after trying settings one by one this was the culprit:
setting it to on like it was on AC by default solved the issue and now on battery mode the consumption is about the same. as on AC, which is actually a bit disappointing, shouldn’t it be less?
Well as it turns out, TLP’s setting to disable turbo boost when on battery is not working, so I ran
echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo
and that dropped me by about 3-4 watts.
I then went to the frequency settings for the igpu in TLP and set it to the lowest I could, this netted me another 3-4 watts of savings, so when idling now on linux I’m using about 22w give or take. but it’s fairly stable unlike windows which was jumping around a bit. As far as idle powersavings are concerned this leaves me satisfied.
I also tried to power off the nvidia dgpu (major hassle) and that only netted me around 3w powersavings, a pittance for how much trouble it is ( I would still take it but when I do it my PC will become kinda crash happy, the kind of crashing where even sysrq doesn’t work)
So the next thing to try was how it fares under light loads.
I loaded up some youtube vid on windows, and it ran 22-24w
I loaded a vid up on linux, it ran ~28w
Which is pretty good to be entirely honest… Yes it’s very impressive, but windows showed me it can go lower, so I want to see if I can’t get it lower however I am out of ideas for how to squeeze the power usage further down than this.
So I was wondering if anyone has any ideas about what I could do?
Note: One other thing I have tried was forcing down the maximum CPU frequency as low as I could make it go but it gave diminishing returns pretty fast (going down from 2.2ghz to 1.5ghz is about 1w, going donw to 800mhz gives about 2w; it doesn’t really seem worth it)
Note2: Using kernel 5.18 negated all my power savings from TLP for some reason; 5.15 and 5.17 work great though.
Update: New test case, I played Kotor on Windows and Linux, on windows it was fairly stable around 28w, on linux it was 32w, a 4w difference again, similar to the one between playing youtube vids.
Start here (updated post): Aggressive powersaving? - #37 by rabcor
The short of it is that I’m mostly satisfied with my results, after wrestling withlinux through various software and system calls I’ve found a way to reduce my power draw from 50-160w to 18-32w if I go as extreme as i can on the powersaving, windows at best can go down to 16w but would generally hover around 25w with regular unexplained spikes into the 40s.
I’m still very much open to suggestions how I could improve this any further, but I feel a point has been reached where lowering power draw further would be very difficult.
I just really wish this stuff was easier, my eyes have been opened to the fact that linux has a pretty big problem with user friendliness when it comes to powersaving/battery life optimization.