Your PC: Leave It On or Turn It Off?


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Jul 22, 2005
The question has come to me in the past: A distant relic of a time gone by. But today, it is a featured story on both Link Removed and Link Removed. This is an age old question for computer users by now, and especially technicians.Mr. Link Removed from PCWorld writes:

Call me a tree-hugger if you must, but I see no reason to keep a computer on when it's not in use. That wastes electricity, which is bad for your pocketbook and bad for the planet. And it's probably bad for the computer.

Most consumer computers are made with low quality parts. They still using SATA or IDE hard drives and earlier processors. While they are monsters at power consumption, they afford no benefit to abruptly powering down and back up. The majority of the computers in the world are not home built and do not use modular power supplies. They use cheap ones. That can explode. Literally. Go on fire. And explode.
Better power supply construction, power line filtering through UPS, and voltage regulating may make it easier to promote green computing. At an organization where I once worked, there was an effort at the main and remote offices to “go green”. An amicable goal, since federal grant loan money was being flooded into the main office. Who better than to fulfill these contracts than the one and only employee in the entire IT/MIS department with 150+ computers? Yes, I developed netlogon and power management scripts to deal with the role of performing all sorts of tricks while people were offline. At night. The computer would chkdsk, defrag, and perform all sorts of maintenance routines from the server command-line. After all, I had actually connected many of these client computers to the domain controller server for the first time, and brought about remote access via VNC and DYNDNS, instead of allowing them to remain dormant and un-updated.Suddenly, someone decided to “go green”. As you can guess, this destroyed my plans to actually create an environment where four to ten year old hard drives did not fail in Windows XP. Some of the employees kids might have been younger than the computers we were using. So I have a unique perspective about an enterprise environment “going green” to save electricity.

The intrinsic argument and belief system in shutting down the computer at night is flawed if any of the following are true:

The computer runs maintenance tasks at night that could not be performed during the day, under any circumstances, and would actually save more money on replacement costs over the long-term than short term electrical costs.

The processor has automatic power state and stepping change support.If the systems can go into relative standby or hibernation, there is no reason to create a power management policy that completely shuts them down. The difference between full power-on and standby can be 100 watts+ vs. <10 watts in standby without hibernation.
Link-state power management allows devices, including hard drives, to stop spinning, even if the entire system is left on. This means your computer reduces significant peripheral electrical usage even when the computer is left on.

If the computer was built with dual core or higher technology, the power exerted by the CPU is so low when the system is idle, there is no tangible benefit from turning the system off.
If the graphics card is on-board or embedded, it likely uses very little electricity. Similarly, newer video graphics cards from NVIDIA and AMD use less electricity when not in use.

Mr. Spector continues:
A shutdown PC will give Windows a fresh start, clear of any digital cobwebs it acquired since its last boot. A hibernated PC will wake up where you left it, with the same programs, files, and windows open.

Unless you use hibernation, turning the computer completely off will always save more electricity than leaving it on. But the question is whether or not this is really cost effective. In my opinion, that answer is almost always absolutely not: There is no benefit to turning the computer off unless electrical fees outrun the cost of replacing a power supply, hard drive, or other modular component. While environmental factors may be an issue, they are extraordinarily minimized when a system is in a low power state of readiness.

This is a matter of measuring power efficacy vs. hardware reliability and making both a risk assessment and policy that is based on logic and not on a whim or political theater.
Leave your computer on if you want to maintain your PC’s longevity. The small nuances of powering the system on and off 365 days a year have the same hosing effect as turning a light on and off, except you are potentially dealing with tens of thousands of dollars of equipment when this policy is employed in a group environment. Administrators at data-centers do not simply turn all of their computers off every night, even on systems that may only have time-based roles. Perpetual and constant changes in temperature, as well as the millisecond over-volts that can and do take place when powering on a system, severely damage the longevity of the motherboard, CPU, hard drive, and graphics card. SSD or SAS disk drives are another reason to leave the system on, as the memory-based storage of a SSD does not run on magnetic resonance and moving platters. SAS/SCSI drives are made for industrial use and designed to read/write 24 hours a day.

However, even conventional hard drives, as we said, can and will shut down, using link-state power management, when the option is configured correctly. Leaving a computer on 24/7, for literally years, will result in minimal hardware issues.
Sending 150 watts of electricity and .5-1.5 volts of electricity to a motherboard and microprocessor 365 days out of the year, however, is likely to ruin you. Constantly parking and unparking hard disk headers on a conventional SATA drive and the blast of wattage that goes directly into the device is no joke, and bursting a transistor on a motherboard should not be left out of the equation.

Often times you will see companies that make consumer motherboards like Gigabyte boast that their motherboards support 100% ferrite cores. Their ferrite cores help conduct electricity more effectively and prevent transformer meltdown, reduce resonance noise coming off the board, and restrict interference. These high quality components attempt to shield a computer from misuse, and from the abuse the computer will no doubt take form being shut down and turned on every single day of the year. A computer is not a person and does not need to go to bed at night. In fact, it actually makes the computer much more tired and age more quickly.
If you don’t believe me, just look at statistics. Powering systems on and off kill power supplies, while switching power states from S1 to S6 do much less damage.

Mr. Lincoln Spector seems to be far removed from the subject he is writing about. Instead of using scientific, or even extemporaneous data, he seems to ramble on about cobwebs. In real IT, we clear out cob webs with cans of compressed air.
He could have used Link Removed: “Turning the computer off can save your company money. According to the study, a U.S. company with 10,000 PCs will waste $260,000 in energy throughout the year due to computers that are powered up when no one is using them.”Instead, he talked nonsense. The reality is that computer components suffer from power on/power off, but are increasingly designed to withstand that blow. Look to see how much it would cost to replace 10% of those 10,000 PC’s if your power management schema inadvertently leads to data retention and/or system failure.With power consumption requirements decreasing, and, arguably, semi-volatile memory becoming in vogue for mass storage, I say leave it on. And with incompetent government agencies still looking to "go green" to get just a few more thousand dollars of that federal stimulus money, you bet I'm a bit perturbed. All the best.

W/out restating the reasons why (but, I will anyway, lol)... sleep, sure but, leave them on not, fully Powered OFF.

1. It's better for or on electronics, can increase longivity. It's hard on them being shut on & off. Uses less energy letting them idle than turning on & off.
2. The amount of current they draw whilst idling or sleeping is almost immeasurable.
3. Powered off 'Automatic' functions don't/can't happen.

My original background is recording studios & broadcast locations (many other electronics based environments are the same) gains, on amps & so on, get turned down all the way but, power is left on, unless & except, if & when periodic maitenance is being performed.


I'm with you on that, Drew. Usually the only time that I reboot is when switching to another OS, or Update Tuesday comes around.

I like putting my computers to sleep, so that they resume fast. Even when using my notebook on battery power, I let it sleep, because fully shutting it down & restarting consumes more juice than letting it sleep for 10 minutes. In fact, one day I forgot to shut it down while on battery, and it was 3 days later before I noticed the flashing light to remind me that it was in sleep mode.

What surprised me was that the battery still had over 70% of it's juice left. I had ran it for about 30 minutes before putting it to sleep.


sleep sounds better, and seems better than hibernate was, is hybrid sleep activated by default if hibernate doesn't show?