I’ve got the power.
So, Im back from vacation. One of the things I did was reorganizing my hardware, and for doing so, I bought a wattmeter to measure what my machines and toys actually consume. A lot of the stuff was what I expected, but there where a few nasty surprises:
| (all values in Watt)
||Ideapad S12||Thinkpad W520||Bertha||TV||Pandaboard ES|
|power supply only||0||0.2||2.5||0.3||0.1|
|desktop w/o display||13||10||122||130||6.1|
From this set a few surprising takeaways:
- The wimpy Ideapad S12 with its Atom CPU eats more power when idling than the Thinkpad W520 with its beefy i7 Quad-Core and 16GB of RAM (13 Watts vs. 10 Watts).
- My TV doing nothing but waiting for the remote to tell it to turn itself on eats more power that each of my notebooks (15 Watts vs. 10/13 Watts).
- Running my desktop (Bertha) as an tinderbox for LibreOffice 24/7 would cost me ~1.000EUR per annum. Doing it with three of those boxes would a very expensive and noisy alternative to what others sell as a room heater.
- My TV eats 30 Watts more when displaying the black screen of a disconnected HDMI signal than with normal TV display. Maybe its expensive to search for a signal?
- Compiling LibreOffice without ccache on my Notebook kicks the power consumption to 90 Watts — but only for a few minutes. Then the thermal controls throttle the machine down to 70 or even 35 Watts, which seems all the machine can disperse over sustained periods.
And then there where these leftover pieces to measure, no surprises there, just a confirmation of my suspicion that the old Asus notebook I run as a home server is eating way too much power:
|(all values in Watt)
||bits and pieces|
|mic preamp off||1.1|
|mic preamp on||10|
|“home server” (decommissioned Asus Z53 notebook)||30|
My tentative conclusions are:
- replacing my old “home server” with something ARM-based like a Raspberry Pi or a Pandaboard breaks even after one year — I should do that.
- Even when under load, a ARM-based Pandaboard has a modest power consumption.
- I will completely turn off my TV on principle as the standby consumption is just pure impudence. As a bonus it prevents my BluRay player from kicking on the 100 Watt TV when I throw in a audio CD (Thanks Panasonic, for providing this excellent and “useful” integration).
- A cheap Netbook might be less powerful, but it hardly consumes less than a high-end Notebook when idling. You get what you pay for.
- I bought a cooler for my Notebook, hoping to unlock it from choking itself with thermal restriction. It should be a good idea in general as the logs not only talked about throttling, but also about more scary MCEs.
- Buying a wattmeter is a good decision, when you run nontrivial amounts of hardware.
Addendum: The 2.5 Watts for Bertha when off may seem bad — but its not at all, if you consider it is running a lights-out management on that.