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Well, today’s “blog-entry” is a copy/paste from my home-site’s “articles.html” page: http://users.volja.net/tayiper/articles.html; in particular it’s the a bit shorter and modified version of the entry titled “RUNNING A COMPUTER NON-STOP OR NOT”. Although I know that copying/pasting of my own content is allowed, I don’t have such a “good feeling” about it, but I think that this article might help many members of this ours Senserely community …

The debate concerning the question “is it better to leave computer running or shut it off” has been questioned since the beginning of computers. The answer has more to do with the type of computer, patterns of user’s usage and a concern for power-bills. You see, it’s that many manufacturers of various specific computer components (like hard-drives and power supplies) have used the MTBF ratings (MTBF means “Mean Time Between Failure”), to express the life cycle of their products. This is estimated frequency of mechanical failure based on stress testing. Note that “Mean” means that 50% fail before that point and 50% fail after that point, i.e. it is not a prediction of minimum life nor a prediction of estimated life. Power supplies have published ratings such as 50,000 hours (a bit under 6 years) and hard drive ratings have been 300,000 hour or even higher (it’s a bit over 34 years), however, note that many computers are running 24 hours a day, 7 days a week, 365 days a year. For example every network-server musts be running constantly and generally they use the same basic components as the average user. But just because we know that the components are capable of running all of the time (be it “full load” or not) does not mean necessarily that they should. Laptops in particular have a higher chance of heat-related problems (because they have very limited ventilation systems), so in addition to the obvious battery power savings, shutting them down when they are not being used will allow them to run cooler and generally more efficiently. So if you use your computer constantly throughout the day, leaving it on during the day and turning it off at night makes perfect sense. If you only use it to check your e-mail once in a while, turn it on when you need it and turn it off when you don’t. If you are like me and have a high-speed cable modem, get tons of e-mail, and hate to wait for Windows to boot, leaving your computer on all the time will probably increase your quality of life. If saving electricity is your concern, then the monitor is your biggest enemy. Your display screen is the biggest single power consumer, so you can simply turn it off whenever you are not using the computer, but leave the computer itself on so you don’t have to wait as long when you want to use it.

A monitoring of new computers at the Iowa State University found that the average computer running “all-the-time” costs only about 65 US-dollars per year. If you were to shut your monitor off on nights and weekends but leave the computer running, the cost would drop to about 40 dollars per year. If you turn everything off at night and on weekends, the cost would drop to about 21 dollars per year. Power-saving systems are now a part of almost every computer/operating system, which will put your computer and monitor in “sleep mode”, which in saves electricity. So there is no one answer for this question, but there are a few absolutes for those that plan to keep their computers running all the time. The first general recommendation would be to invest in a good surge protector with a UL 1449 rating or, an UPS (Uninterruptible Power Supply), since the likelihood of a power related issue increases with the length of time that your computer is running. The second is to always shut down and un-plug your computer during an electrical storm (cutout of a circuit or power outage/failure). There is no way for your computer to get hit if it is not plugged-in, and it is a cheap way of protecting it your computer.

But on the other hand, I was told on Ars Technica forums (and it surely sounds logical) that once an electrical device such as computer is powered-up, it appears to be the best thing to left it on running non-stop. The application of power in cycles of on/off is damaging to a computer, i.e. it is damaging almost all the crucial components including hard-disk, processor, graphic-card, buses, mobo-chipsets, various “inner circuits”, probably also RAM etc., and shortens a particular device’s life-time. As opposed to many components, motherboards in particular are a fairly “binary creatures”, meaning that they either work or they don’t. Also I suggest you to see the “20.9.2005” entry on the “events3.html” page or check the “Theoretical question regarding DC-projects and 100 % CPU usage” thread: http://episteme.arstechnica.com/groupee/forums?a=tpc&s=5… for further info. In this one we discussed what a heat actually does to the processor and other hardware-components (especially see Rarian’s posts); in one sentence, the problem that arise from heat, particularly a temperature cycling leads to metal fatigue and the increase of speed of chemical reactions, so the bottom like is that running you computer at a constant high temperature is better than running at an oscillating high temperature. Also computer as any mechanical device sees most of the potentially “damaging” stress during the power on/off cycling. Actually, I am planning to write a full article about it in the near future. Another interesting related thread is the “Is there a limit on/in a number of “page faults” for a process ??”: http://episteme.arstechnica.com/groupee/forums/a/tpc/f/99609… one that I’ve also opened on Ars Technica forum back then. It deals mainly with the problem of endlessly increasing number of page faults for the “svchost.exe” process, i.e. particularly the one launched with the “-k netsvcs” switch and in my case hosting no less than 16 NT-services.

P.S. - Anyway, as a general rule, I would say that because of the reasons mentioned in the above paragraph, it’s better for desktop computers to NOT to shut them down too often, but especially not every night. I surely do run my computer 24/7, and there are no signs of any harm being caused by this !!

Ivan Tadej (user: “tayiper”)

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