Best UEFI/BIOS settings for power savings (intel 12gen)

[barleycabbagefishbee]

Hey,

maybe it will be a bit strange, but I want just to set proper power savings options on my PC - do not overclock anything, use only for work, in most of time do not use full power, so why waste energy (and pay higher bills)?

My config:

• i5-12400 (non-BOX cooler)
• 2x 32 GB DDR4 Corsair Vengeance LPX 3200MHz
• MSI PRO B660M-A
• Samsung 980 NVME
• Be Quiet Pure Power 11 400W Plus Gold

I've already changed a lot of settings in BIOS, but not sure all of them.

List:

• enabled XMP for RAM + memory try from MSI (it offers better timings), also decrease voltage from standard 1.35V to 1.25V - super stable so it looks fine
• changed CPU Core Voltage Offset Mode to "-"
• changed CPU Core Voltage Offset to "0.050" so CPU is undervolted (it's max value I can use)
• changed CPU Lite Load to "Mode 1" (super stable)
• changed Intel C-State to Enabled
• changed C1E Support to Enabled
• changed Package C State Limit to Auto
• changed EIST to Enabled
• changed "ErP Ready" to Enabled
• changed "USB Standy Power at S4/S5" to Disabled (no need this feature)
• changed "Native PCIE Enable" to Enabled
• changed "Native ASPM" to Enabled
• changed all PEF 0/1/2 ASPM to "L0sL1" (based on info from internet)
• changed all PCI Express Root Port ASPM to "Auto"

Anything else should I change or maybe something to adjust (I'm not sure especially ASPM items)?
So far computer is quiet, max. CPU temps are ~55 Celsius do not see any performance drawback

 

[Wirko]

If by any chance you have a power consumption meter, can you tell how much your PC consumes now?

 

[barleycabbagefishbee]

Today I spend some time and tested that using power meter
Results are interesting.

Idle: no internet, stabilized after login into system
Load: prime95 small FFT (max heat/power) after stabilization
Changed power limit to 255W to avoid PL1/PL2 changes during test

All except offset (only Lite Load 1)
~26-26W idle / 128W load on 6x 3,99 GHz

All except Lite Load (offset -0.05V)
~26-27W idle / 136W load on 6x 3,99 GHz

All (Lite Load 1 + also offset)
~25-26W idle / 112W load on 6x 3,99 GHz (!)


So it looks like both options are not in any conflict!


Checked other items like EIST/C1/C-States and some additional thoughts:
- disabling all of them: result is ~37W in idle and additional 2-3W on load in idle so it's definitely NOT good choice
- EIST enabled = CPU moves down to 6x ~360 MHz on idle but it is NOT reflected on power usage - after disabling CPU is was 6x ~4,1 GHz but power usage was the same. I think disabling EIST may be beneficial because no time to change clocks (it's important on mobile, not on desktop), but want to analyze deeper

ASPM
- moving to disabled = controlled by BIOS => 20-22W on idle, no changes on LOAD, so I decided to use this new config


Overall, final result is 20-22W on idle and 112W on load
Based on possible changes, it's huge - lite load and offset have big impact on power usage and temperatures.
These additional 10-20W = ~7-10 Celsius more during test

 

[Wirko]

Lots of useful info for those trying to build a low consumption PC, thanks! SilentPCReview was into that and had many good articles and tests but they are long dead, only their archive is still online.

I'd also try lowering RAM speed to ~2400, you may save a little bit of power but losing performance may not be acceptable to you.

Regarding ASPM, I'm surprised Windows can't manage that properly, or maybe it does, after a long delay. Some reviews used to measure power twice, "idle" and "long idle". What power plan have you chosen?

 

[barleycabbagefishbee]

I've checked also powercfg -energy and with disabled native ASPM, Windows reports that as error:

Platform Power Management CapabilitiesCI Express Active-State Power Management (ASPM) Disabled
PCI Express Active-State Power Management (ASPM) has been disabled due to a known incompatibility with the hardware in this computer.

It's possible, that for long idle, it may be more beneficial than controlled by BIOS

One additional observation not related to BIOS settings: I use WSL (Windows Subsystem for Linux) and installed Hyper-V from Control Panel > Optional elements
It prevents the system from hibernating properly (sleep mode worked fine). I thought it was related to one of these BIOS settings, but not. Hyper-V causes issue, it's not required for WSL so I disabled that