How to reduce electricity consumption

[gusto]

I recently saw this procedure as a way to reduce electricity consumption.
I set it up the way the guy describes it

echo "powersave" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

It is set from 7:00, see graph.
The CPU increased from 2% to 4%, but the total consumption decreased by 3-4 Watts
Is this setting ok? Doesn't the CPU suffer?

 

[leesteken]

The CPU increased from 2% to 4%, but the total consumption decreased by 3-4 Watts

The CPU runs slower, so it is more busy. Are you measuring power over time? If it uses less power but uses power for longer, then it might not help you or make things worse.

Is this setting ok? Doesn't the CPU suffer?

It's fine for the CPU. You need to measure power usage over time to make sure it helps you.

 

[Dunuin]

Depends on the CPU. With some CPUs the "powersave" governor will limit the CPU to the minimum clock and won't allow it to clock up at all (in which case the "schedutil" governor might be better). With other CPUs it just tells the CPU to clock down more often but it still allows it too clock up when needed.

And best way to save electricity of cause is to only run a PVE server when needed. I for example got another small homeserver that runs the stuff that needs 24/7 availability and the big server only runs on demand when needed. So I can shut the big one down when not at home or while sleeping.

 

[gusto]

It's a home server and it's idle a lot of the time.
CPU is Intel Core i5-10400, MainBoard
If you know of any settings to reduce consumption, I will be grateful

 

[Dunuin]

You can install powertop. Useful to see what's going on (clocks, c states, consumption, cpu time, ...) and it will show you if there is something that can be optimized (link power management, autosuspend, runtime PM, ...).

 

[LnxBil]

And best way to save electricity of cause is to only run a PVE server when needed. I for example got another small homeserver that runs the stuff that needs 24/7 availability and the big server only runs on demand when needed. So I can shut the big one down when not at home or while sleeping.

This. Anything else will not accomplish much.

 

[Jarek Hartman]

If somebody interested in real-life data:

• An idle system with AMD Ryzen 9 3900XT 12-Core Processor, 6 HDDs, 2 SSDs, ..., etc
• As per lscpu, CPU max MHz: 4775.9761, CPU min MHz: 2200.0000
• Default scaling_governor = performance
• Tuned to conservative (using `cpufrequtils`)

Average power consumption dropped down from 112 Watts to 91 Watts:



So pretty substantial difference (18%), without any noticeable performance hit for the workloads I run.

Thank you,
Jarek

 

[vendo232]

I`m running Z4G4 HP Workstation

The difference between performance and power safe is 20W



powersave


performance

 

[Jarek Hartman]

2.2 Powersave
-------------

The CPUfreq governor "powersave" sets the CPU statically to the
lowest frequency within the borders of scaling_min_freq and
scaling_max_freq.

2.5 Conservative
----------------

The CPUfreq governor "conservative", much like the "ondemand"
governor, sets the CPU frequency depending on the current usage.  It
differs in behaviour in that it gracefully increases and decreases the
CPU speed rather than jumping to max speed the moment there is any load
on the CPU. This behaviour is more suitable in a battery powered
environment.

I set `powersave` only for the night, when not running my daily workloads. During the day, when my CPU-hungry workloads are started, I'm back to `conservative`. When in `powersave`, the workloads are too constrained (as the CPU is on `scaling_min_freq`) and timing out.

Best regards,
Jarek

 

[zenowl77]

check your bios, i would disable turbo boost (examples of stock TDP vs Turbo boost power usage below) i personally always get rid of it on everything. just isn't worth it in my opinion.



for example according to this your i5 can jump from 65w to 134w max under turbo boost, so load can cause quite the increase in power usage.

check your bios for other settings / options, personally i have a i7-7820x and i lowered my TDP from 140w to 120w, dropped my clock fro 3.6ghz to 3.3ghz and set a setting that allows a percentage drop in TDP if max usage is hit for x amount of time to 20% after 2 min, so if anything keeps my cpu maxed out for a long time it drops from 120w to 96w (still thinking about tuning it down a bit more and benchmarks i have ran have shown very minimal impact. about 5-7% if i remember correctly which is acceptable for about a 15%+ drop in power use. )

you can also consider undervolting / underclocking if you're really serious but you have to be very careful and ensure stability if undervolting your cpu, (probably is not worth it or recommended but could be an option it it just HAS to be even lower) it can lead to hardware damage or write errors, etc and the last thing we want is hardware damage or data corruption.

if you have a Nvidia GPU you can use nvidia-smi -i 0 -pl 60 0 = gpu number, 60 = watt limit, check your gpus, what they run at and what works some only play well with being dropped just slightly, others work pretty well with fairly huge drops and it can save you 50-100w+ under gpu load on some beefy cards. i usually keep mine at 60w max, the lowest setting which they thankfully handle well.

of course if you are ultra serious and/or have money to invest, do whatever you can to minimize parts. every extra part is more power usage. (some more than others), SSDs/NVMEs are best on idle power usage but for HDDs helium drives shave a little off the consumption of power and save a couple of watts each. (i believe usually its like 5.4w instead of 8w or so, if i remember correctly from last i looked them up when i bought a few.)