PC Power Consumption.

SIW2 · 25 Jun 2022

I am playing with one of those power meters . this kind of thing
Amazon.co.uk : power meter

It reports 1.9 w with the pc plugged in at the wall, but not powered on.

b365 motherboard, i5-8400, 2x8gb, Bequiet 11 400w gold modular psu.

1.9w seems quite a lot when it is not switched on.

The pc above idles on the desktop at 19 point something w. It currently reports 20 point something as I type this ( firefox, 2 tabs open)

---------------------------------------------------------------------------------------------------------
I just tried it with an ancient HP8300 sff ( intel 3rd gen cpu ) and that reports as 0.9w when powered off which is more in line with what I expected.

The hp 8300 sff reports 14 point something idle on the desktop and 15 point something on this site with a couple of tabs open.

It seems to consume quite a bit less power than the more modern pc.

The hp 8300 currently has an i3-3220. I might buy a 3rd gen i5 to see if that makes any difference. I have a 3rd gen i5 in another machine, but I am reluctant to swap that in because that has just the stock cooler which is a real nuisance to get back on as the plastic tips splay.

SIW2 · 25 Jun 2022

You can have hours of fun with these little power meters.

I notice that turning off the sata ssd and plugging in my nvme disk increases power consumption by about 1 watt.

I checked the table lamp on my desk which has bulb allegedly using 15w and it reports a steady 15.5w . So it seems quite accurate.

The router uses 7.1 watts

This monitor is the power hog at 34 watts.

So the pc, router and monitor total around 61-62w when pottering around on tinternet.

hsehestedt · 25 Jun 2022

As for the original issue, a power consumption of 1.9w, does your computer have Wake-on-Lan enabled? If so, the Ethernet adapter would need to have continuous power. Also, are your USB ports configured to provide power when off? Likewise, if your computer is set to wake when the keyboard or mouse is used, those devices need to be provided power.

I'm not at all trying to minimize the question, but I was curious what that would cost in energy usage. Where I am located it works out to about $1.50 per month assuming a 1.9W draw 24 hours a day.

SIW2 · 25 Jun 2022

It is odd the much older pc uses less.

are your USB ports configured to provide power when off?

yes. all my machines do.

hsehestedt · 25 Jun 2022

I wonder if some of that could be simply due to how efficient or inefficient the power supply itself is at extremely low load levels.

SIW2 · 25 Jun 2022

If one is 72% efficient at 20w and another is 75% efficient at 20w, that is only 3% of 20w different.

Most power supplies dont do well at very low loads. I suppose the psu that are fanless at low level dont use the 1 or 2w that a slowly spinning fan would consume.

None of mine are fanless, so its not the reason here.

Unless those oem psus like in the hp 8300 are optimized more towards low loads.

Steve C · 26 Jun 2022

My PC consumes 0W since I always turn it off at the mains when not in use!

hdmi · 26 Jun 2022

Time to buy an Enermax MaxTytan.

SIW2 · 26 Jun 2022

Steve C said:

My PC consumes 0W since I always turn it off at the mains when not in use!

So do I. But many people don't.

I just checked a gigabyte b75 system of 2012 vintage. Also 0.9 watt when powered off.

Might be some bios setting in the b365 that is causing it to use 1.9w

Helmut · 26 Jun 2022

PC PSUs are very much less efficient at very low power draw, so much so that what you are actually measuring is the power dissipated in the PSU, not the MOBO/standby components still powered on shutdown.
Probably 1.8w of the 1.9w is dissipated in the PSU.