Ask HN: Should I turn off my idle machine over the weekend? | Hacker News Reader

Ask HN: Should I turn off my idle machine over the weekend?

42 pointsrahulskn8658 comments

Monitors turn off automatically, Processor: Intel Zeon E5-1660 16 core, 3.2 GHz, Memory: 64 GB, Typical apps open: IDE's and browser, OS: Linux Ubuntu 16.04.6

How much energy am I wasting?

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> How much energy am I wasting?

Plug it into a kill a watt meter and find out: http://www.p3international.com/products/p4400.html

Out of curiosity, how often do you use a Kill A Watt meter? $23 seems like a high price just to plug a device into for a couple days to say "oh maybe I should turn this off more often"

Myself? Never, as I don't have one. When I want to find out what a device is consuming, I hook it up through my Fluke multimeter to obtain the current draw, then calculate the rest.

But, for general use by anyone not a EE or Electrician, hooking up a general purpose multimeter to mains power to measure current draw is a not recommended, much danger here, operation.

Therefore I erred on the side of caution and recommended the method that was most safe for all involved in all situations.

What I suspect you will find, however, is that you will find uses for the device that you never anticipated once you have one.

Many libraries have them to check out for a few days.

Some community share programs lend them out for free. Including some libraries:

https://seattle.bibliocommons.com/item/show/2655545030_kill_...

I've always had the same concern stopping me from getting one. I wish I could go to Best Buy or someplace and rent the darn thing for a few hours instead.

The kill a walk is really handy for debugging battery charging. I seem to use it on a regular basis, but I tinker with stuff a lot.

cheaper to buy smart plugs. https://www.amazon.com/Etekcity-Monitoring-Required-Warranty...

This is the comment I came here for. I bought a Kill A Watt some years ago when I wanted to get a feel for what my devices were using and can't say enough good things about it.

For USB, I also recommend a USB Power Meter: https://www.amazon.com/gp/product/B01J7236K2 to see how much current your peripherals use when charging/when full.

Many UPSs also will report power usage.

Your computer probably consumes about 100W when idle. The difference between on and off all year is https://www.google.com/search?q=100%20W%20%2A%201%20year%20%... But the weekends would just be $30. If you have reasons to log into your machine remotely that are worth more than $30/yr, then it's worth it.

Wake-On-Lan was good for exactly this kind of use case, but it never quite picked up.

Also newer PCs generally use less than that, probably closer to 50W idle?

I use Wake on LAN on my Desktop PC/Plex Server and it works great. I still need to setup shutdown remotely which I could probably just do with ssh or something similar (I don’t think I want to go as far as Remote Desktop mainly for security reasons). Anyways, I’m curious as to why you said it never picked up. Do you say that just because it is not yet popular, not widely supported, or because it is somehow flawed?

never quite picked up as in got so standard and ubiquitous you dont even notice it?

Is to built into Remote Desktop clients? Doubt it.

> 100W when idle

That's significantly off - my Skylake desktop PC idles around 15-25W (I just checked with a kill-a-watt).

Hmm, I've always used 100W as a reference. Maybe I got that from server estimates?

It used to be a good estimate not so long ago. Things have improved dramatically recently

You see the same on laptops. Each generation seems to come with a smaller wattage brick

That would be more like it. 100W for an idle desktop/laptop PCs sounds pretty high.

My dual socket Xeon desktop half a decade ago idled at 94W.

Thanks for reminding me that I exceptionally turned off my office PC today, leaving inaccessible the latest version of a paper I need to submit this weekend Today, it wasn't worth the savings.

If your main use is sharing files, any cloud drive would take care of that. Besides the money, it's wise not to waste resources needlessly.

Clearly, there are better ways to share files than scp from work desktop.

I should have said that having forgotten to push changes to a remote repo, turning the desktop off partially caused quite a bit of extra work in an already very busy weekend. I value that wasted time and energy more than the electrity that would have been wasted had I left the desktop on.

Saying that it's wise to turn the PC off has no effect on the large swathes of corporate developers who only see an off PC as potential waste of time.

Question: Other than energy wasting, is it harmful to computers to allow them to idle? We leave dozens of desktops on all the time at my work...most people never even shut theirs down for months.

It's unlikely that this would matter to most people, but leaving the computer sleeping rather than hibernated or shutdown partially defeats any full disk encryption. Recovering keys from RAM is possible for a short period of time after power is removed. [1] Microsoft suggests disabling sleep when using bitlocker encryption. [2] And it is similarly suggested that Ubuntu use suspend-to-disk (hibernate) rather than suspend-to-RAM (sleep) when utilizing full disk encryption. [3] For better security leave the computer shutdown when not using it.

1. https://en.wikipedia.org/wiki/Cold_boot_attack 2.https://docs.microsoft.com/en-us/previous-versions/windows/i... 3. https://security.stackexchange.com/questions/208921/is-suspe...

Likely the bigger impact is on the HVAC cost. Test it out some time. Have your facilities team show you HVAC power consumption for a month. Then for a month, turn off all the PC's on the weekend and after hours.

Technically yes. There are 3 types of phenomena that cause transistors to degrade or fail. All 3 are caused by electrons flowing through the gates. See https://semiengineering.com/transistor-aging-intensifies-10n...

Practically speaking, however, I doubt it makes much of a difference for most desktop systems.

There's way more in computers than transistors ; you have to weigh that against the other effects on the complete system. I would be surprised if the thermal cycling from shutting down and booting the computer wasn't orders of magnitude more likely to cause problems than actual wear on the transistors. That being said, all of these issues are very unlikely to occur.

There's a certain amount of electromigration that happens in silicon transistors with a voltage applied but it scales strongly with temperature so I wouldn't worry if the processor is idle. I suppose mechanical wear on the fans is a concern?

Probably more harmful to the active software session than the hardware. A lot of programs (OS's included) have subtle memory leaks and other obscure bugs than can take multiple days to manifest.

As a Linux user, I confirm that I only switch off my PCs when there is a power outage.

Can't you set it to go to standby after some time? Then it would save energy during the night (or whenever else you aren't using it) as well as at weekends.

You're wasting a fair bit. You can get a qualitative sense by feeling how warm the fan exhaust is: I use my cheese grater Mac Pro to stop my uninsulated home office freezing up in the winter.

However, despite the savings, you may not break even if your PSU fails early due to thermal cycling (probably a rare event, but a PSU for a machine like the one you describe was probably built to be left on in a commercial use case.)

That reminds me of how the main computer lab where I went to grad school was normally quite chilly in the winter, except near finals. The heat generated by all the PCs, printers, and people caused it to be nice and toasty near finals.

Those cheese grater macs are real energy slurpers.

I'm in Sweden. Every year I'm spending April-October in a cute little house built in the 1860s - it used to be the telegraph station for the harbor in this sea-side place back then.

Houses from this period aren't very well insulated (sort of like a contemporary house in California ;) ). So, in April/May/September/October the computers/displays I've brought here are very much a part of the heating. I find this beautiful. They're using like 600-800W at peak, but all of that is being put to use in heating the house. They end up being like 40-50% of the electric heating cost.

(Internet access is provided via LTE. I'm typically getting around 60/30 Mbps. Quota of 50 GB per day. Need to send a text message if you want more.)

any resources on finding and staying long term in cabins/houses like that? I would love to stay 4-6 months in cute little cabins. Vacation rentals aren't really it

In general: I think you need bite the bullet and actually buy one. :)

For Sweden: if you're able to avoid the most beautiful month (july), should probably able to secure something nice for for hire. You should be able to seal a deal renting one of these places from april 1st to just before midsummer eve, an from like august 1st to october 1st. :)

You should anyway, as it's still a waste of energy, but if you are just curious about usage you can get smart plugs that will tell you how much energy a plug is drawing. That would let you see energy usage, and by extension, the energy bill.

Why wouldn’t you turn it off? I would turn it of at the end off each workday. Booting a computer is a few minutes at the most, you don’t need to be up and running within seconds each morning. Push the power button, go get coffee, login, start work.

That's a good advice if you're a clerk. As a developer, I have services, daemons, build processes, open sessions of any kind, it's just simpler to let the PC idle a few hours than restarting all those sessions every day!

Sleep mode handles this already, no?

The only way to know is measuring.

Personally, I don't ever turn my desktop off unless I know I'm going away for at least a week. I've been burned in the past by weird flaky things happening with OS standby and hibernation, so it isn't worth messing with. The other danger is unanticipated OS updates (I have Windows boxes...); I prefer to keep those on my schedule, where I can deal with them, and any resulting fallout, at my leisure.

At the end of the day, running my desktop 24x7 costs me like two or three cups of coffee a month, so I just don't worry about it. It's well below the threshold of things I can spare the mental effort to concern myself about.

Not only should you let it 'idle', you should start hosting servers from home and always leave it on. It's the only form of "distributed" that really works and it gives you complete control over everything.

I think if more people had reliable always-on home boxes, software devs would have a better target for distributed tech (and one would expect it'd be incumbent upon the software to figure out reachability w/ ISP/NAT issues).

Similarly, if more people had always-on home boxes, many mobile apps might be thin clients to at-home software opening up plenty of possibilities. (even a simple VNC-like proxy to an at-home web browser w/ advanced ad blocking or other extensions can help those in walled gardens who could tolerate the latency)

I would think this is much more power inefficient than time sharing.

For single PC's its not a big deal. When I worked at a small college, we started powering down all pc's 3 hours after the last class in the day, and then waking them all up with WakeOnLan about 30 min before their first classes. Since each lab had 30 pc's, it added up pretty quickly. Also, less AC needed, since they weren't warming up the room all night.

This seems like the best plan to me. Nobody wants to wait for their computer to boot when they show up in the morning, but you can still be smart and save some power overnight.

Yes. At least put it in standby and make sure nothing wakes it up while you're gone.

Here, try this: https://software.intel.com/en-us/articles/intel-power-gadget...

What's your GPU?

Modern GPU's support power saving. In linux you can see it with PowerTop and you can toggle it on / off.

powertop is great for figuring out what is bringing the CPU out of idle states too. One tip is to close your web browser as it's probably going to be one of the most wasteful things to leave running.

I think sleep/hibernate is reliable on MacOS and maybe windows.

I wonder about linux though.

Typically commercial OS vendors have enough money to pay someone to make resume work. But all the crazy corner cases might be too much for reliability on linux.

Please correct me if I'm wrong.

https://semiengineering.com/chip-aging-accelerates/ “We are seeing an acceleration of aging where the chip breaks down. “They may be missing clocks or there is extra jitter. Or there is dielectric breakdown. And anytime something breaks down, there is an avalanche of new things you have to worry about. A lot of aging models advanced in an era where electronics were used sporadically. Now chips are running all the time. Inside of a chip, blocks are heating up, so aging is accelerated. From that you get all types of weird phenomena. A lot of companies have not revised their aging models, either. They assumed these devices would last three to four years, but they may fail sooner. And given that design margins from the beginning can be flimsy, aging can throw them off.”

Someone needs to do a good xkcd like visual of the relative energy and carbon footprint of things. You can really see a surge of honest yet weird questions like this from people because there has just really been no good accounting and communication to give people a frame of reference.

Personally this is the one I visualize and use as a mental rubric when people ask about individual behavior options: https://i2.wp.com/shrinkthatfootprint.com/wp-content/uploads... but its a decade old and "average american" centered.

I think it would really help both better decision making and better conversations if people understood that there is no one answer to any of these questions. You just have to rank things by footprint and start at your top. If you're doing things that are #7 on your own footprints list instead of things that are #1 - #3 then you're not being an engineer, you're fretting.

I received an email from the power company last month, announcing they were moving to a time based tariff.

It's not a new idea for me, my previous country has had this for decades.

But the email suggested setting the dishwasher to run overnight, and charging my phone and electric car overnight.

One of these is not like the others. The saving would be a about 40¢/year.

The phone example had been removed from the website, so at least someone noticed. But someone working at the power company wrote that email...

I think what most of the responses are missing is that the power system is designed for peak power consumption.

And any incremental amount of power needed to meet the peak demand is going to come from inefficient or dirty sources.

I asked this question of myself about 15 years ago and decided to only invest in laptops or systems running laptop parts.

One of the things missing is that some LCDs burn a lot of watts so should be turned off too.

PSA: instead of buying a kill-a-watt device rather get a smartplug with monitoring. Similar result except has other uses

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