Power ON or Power OFF
 

I would like to know if it is better to turn your computer off at night or to leave the computer on all the time. What is healthier for OS X and the Powermacs?

As a general rule all sensitive electronic equipment is best left on as this avoids i) unecessary heating and cooling of the circuitry and ii) less power surges that might likewise damage your machine. A good (simplified) example here would be a light bulb. When was the last time you had a light bulb burn out on you after it had been on for a while? Normally, it's the sudden increase of temperature when it's turned on that does the damage.

Sensitive electronics aside, OS X tends to run better if left running. First off, the OS's memory management means that data you use frequently is cached as inactive memory which can later be recalled. This makes things generally run more quickly.

Second, if you leave your machine running overnight the scheduled maintenance tasks will run (providing your machine doesn't sleep during this period). It's important to run these to ensure that the OS runs smoothly.

I've had my machine for just over 12 months and haven't shut it down more than a couple of times during this period and have experienced no problems.

I like to shut my computer off at night. I have a paranoid fear that it will overheat, burst into flames, and burn the house down. I also like to save electricity as much as possible. For that, I used Cronnix to reschedule the maintenance tasks for a time when the computer is actually on.

Dave, do you log out at all? If not, do you keep accumulating swap files? Or do you have enough memory so that it isn't a problem?

[edit]Oops, just saw that you have a boatload of RAM, never mind on that last question. However, it is a consideration for those of us who don't have that much RAM. If you leave the computer on, log out every once in awhile to let the swap files get recycled.[/edit]

My record uptime is 19 days without a restart but I probably logged out numerous times during that period but I'm not sure how many swapfiles I accumulated during that session. My current uptime is 2:9:15 and I've logged out once and have two swapfiles atm. By the way - if you're interested - I've written a Konfabulator widget that monitors the number of swapfiles. Let me know if you're interested - I find it quite useful to have an instant readout on the desktop.

On my system, I find that PsyncX causes the most pageouts. I have it set to back up my user folder every night and often find that it creates a swapfile. The most I've had recently is four. I take your point though - in the absence of ram it's certainly worth logging out once in a while or even restarting. Having said that, what exactly does logging out do for/to swapfiles? When I log out I normally end up with the same amount of swapfiles when I log in again. Does this behaviour change when you have a high number of swapfiles?

I still maintain that providing you can avoid torching your own house, it's probably better to leave your machine on ;)

I've avoided torching my house so far. But I understand what you are saying, and it makes sense. Does that mean you leave you lights and TV on to give them longer life? ;)

I was under the assumption that logging out removed the swap files since all applications were quit. I just tried it, and you're right, it doesn't remove the swap files. Damn. I guess restarting is the only option.

For me, I have noticed that Acquisition creates a lot of swap files, I think it has a memory leak. I have had up to ten swap files created when I leave Acquisition open for extended periods. That is quite a bit of hard drive space. Restarting does clear them and give me the space back. I just bought more memory, so I hope that will clear it up.

I would be interested in your Konfabulator widget, you can post it or send it to me in an e-mail. Thanks in advance.

More later - I'm supposed to be watching a film. In the meanwhile, have you moved your swap location or is it still in /private/var/vm? If you've moved it I'll need to modify the widget.

It's still in /private/var/vm. Thanks for doing this. I really appreciate it.

Now back to the film!

The TV stays on standby but the lights go off ;) Btw, I just sent you a PM as I don't have your email address and you have your preferences set to block emails.

TV on standby -- I'd completely forgotten about that! I spent two terms at a British university and we has a TV in the flat. I was first puzzled, then amused, to find that there were two states in which the TV wasn't on -- standby and off (at least, that's how I recall it). None of the TVs that I've come across here in the US are like that.

Back on topic, I leave my G3 iMac on nearly all the time, but asleep at night and during the day when I'm not around. I think my longest uptime was 37 days once... I think I've read elsewhere that Macs (the iMac at least) draws just barely more power when its asleep than when it's off but plugged in.

Dave (and others), does sleeping and waking the computer cause as much stress on the cicuitry as turning it off or on? Just wondering.

(Current uptime on my iMac is 36 days, 3 hrs., 5 min.; I use it as a web server, printing, scanning, and a file server for our home LAN).

I'm not sure, but would suspect not. My understanding (though this may no longer be all that problematic) is that changes in temperature - which cause expansion and contraction of the circuitry - are the major problem. I guess I can't really answer your question because I'm not sure exactly what gets shut down when the computer sleeps.

What about an iBook? I am always afraid to leave it on because it can get so freaking hot!

Even asleep, closed, and plugged in? I don't own a Mac notebook, so I can't comment specifically, but I'm considering getting one in a couple of months, and I pretty much figured asleep, closed, and plugged in would be the way to leave it overnight, etc.

ebow, i have had a 12" ibook for the past year and two months. i hardly _ever_ turn it off. at night, i just put it to sleep, stare in amazement at the little pulsing white light (still !), and it's ready to go the next day. i have yet to have any problems.

Have you ever left it "on on" all night? Meaning no going to sleep? I am always jealous of the desktop users who can set an away message to "Sleeping", or something of the sort. Trivial, I know, but it still irks me :D.

Also, have you ever noticed that when you leave the iBook plugged in when it is either asleep or off, it makes a really high-pitched whining noise? Yeah, that really gets to me, especially if I fall asleep in front of it ;).

actually, i have left it on many times. no problem there either. i just set the screen to turn off. also, i have never noticed any strange noises, whining or otherwise, from my ibook. what you're describing doesn't sound too normal...

I think you're right about Acquisition having a memory leak. A MAD, ANGRY, VENGEFUL memory leak that can often bring my system to it's knees. Quite an unfortunate thing really.

I've left my TiBook on all night a couple times because it was either compiling or downloading. I don't do it for two reasons: the heat and the noise. My TiBook (500 MHz) gets pretty hot, so I like to give it the night to cool down. The noise is mostly due to the hard drive. I can set the hard drive to sleep when possible, but it usually won't go to sleep (and thus silent) before i want to go to sleep. I guess my Cube has me spoiled, but I want my computers silent.

Leave it all on!
 

I leave everything on. Am I wasting energy or money?

I've read some years back that shutting off flourescent lamps for less than 8 hours was a waste of money and energy. You lost more lamp life and electric energy than you saved.

Now I have some really old stuff I use every day, music systhesizers from the 80's :cool: and they all still work.(except the Prophet 5 which crapped out 2 years ago) Would they still work if I turned them off every day? What would the repair/replacement costs be. Would I even be able to replace them. Or my Amiga 2000 (circa 1985)?

In winter I don't use much heat, but summer AC is killing me.

I've been running my iMac DV sence the day i got it like 2 1/2 years ago, and it has never been turned off aside from Power failures, and it never gets to sleep it gets used 24/7. Although I have lost 3 HD's probably due to the heavy power fluctuations.

My mac never even completely sleeps (displays go off, and hard drives spin down, but if it sleeps, ethernet shuts off). It has been like this for a year (as I've only had it that long). As I understand from the guy I bought it from, he left it running all the time, as it was a server.
I used to leave my powerbook 5300ce running (screen off) ALL the time, and used it that way for about 4 years. I think it was only off in shipping, and tear downs.

Off topic: About EVIL memory leaks. mldonkey 2.02 on 10.2.4. I'd gain about 100,000 pageouts in one eight hour night, and I have 1.75GB of RAM!

I've had various versions of PowerBooks since I got my 190cs (2nd hand). Depending on my environment when I had my 190cs, sometimes I left it on 24/7, because it was my only computer and I wanted to stay online 24/7. To do this, though, I made sure I left enough surface for cooling on the bottom of the machine. After my 190cs, I got spoiled :D and bought my Pismo 400MHz. I don't have the same environment that I did when I had my 190cs, but with the heat generation that this computer puts out, I don't think it's best for the system. I've often fallen asleep with the system still "on on", and by morning, it is really hot where it was sitting. I often close the shell and let it pulse sleep and wake it up tomorrow morning. I also excersize the battery by draining it and then charging it at night when I sleep. It's time for a recondition though (2+ years).

My other computers, which are towers, I leave on 24/7. I just turn off the printer and any periphials that I don't use. I.E. Speakers, Scanner, Monitor(s).

It is much less wear and tear on desktop system to leave the hard drive to never spin down, but to use power saving on the monitor. The CPU (in general) sometimes has trouble waking from a sleeping state as the computer gets older. Laptops are more expected to shutdown/restart (which also spins down the drive before the chime) and sleep than desktops are. I would HOPE that the laptops would have a longer MTBF on the hard disk because of this factor.

My 2 Cents.

MTBF = Mean Time Before Failure (life expectancy)

--TJ

To Thundarr...
hi.. you mentioned using Cronnix to change when your Cron Tabs run. Help..How do I use this thing? I downloaded it but cant figure out what to do with it...
Thanks
Jerry:

Re: Leave it all on!
 

I read recently that this is a myth. I'd post a link, but my brain's been turned on and off so many times that I think it's wearing out... :)

myth?
 

nkuvu

You could be right. I'm sure that I read this in the 80's. Energy costs, manufacturing costs, and labor costs (to have someone flip switches) have all changed.

But there is a break even point somewhere even if it is less than an hour.

In my experience those flourescents that have a seven year life warranty seem to need replacing every couple of years or less. But like anything else that is cheap, it costs more for shipping and handling than to buy another outright.

And how about that government recommendation to shut off your engine at stoplights. Goodby battery and starter.

I'd seen this thread a couple years back, when I had gotten my G4 mini. For convenience, I chose to leave it on most of the time. Approximately two years later, the Seagate HD in it was dead. I know this can happen to even the manufacturers which have the best reputations, but two years?

This was the first computer I've ever left on most of the time. While unix was built, I've heard, for mainframes which were left constantly on, I don't believe the G4 mini was built for that. In retrospect, I believe I should have been turning it off at night, so as to avoid heat build up.

When I pulled the dead HD out, I saw scorch marks on the base. There was tremendous dust build up within the case on the fan and most other components. I think that this was a factor in its dying. Perhaps if I had regularly opened the case and blew compressed air through it, it would have lasted longer.

I'm now booting it from an external HD when I need to use it. Primarily, I'm using a macbook pro, which I don't run all night. It's off, recharging during the night. In Terminal, sudo periodic daily weekly or monthly takes care of the maintenance tasks.

I believe that the larger macs, such as the iMac and Mac Pro, which have better ventilation, will be okay to leave constantly on, but I'd hesitate in the future to leave a mini on round the clock.

To sleep or not to sleep
 

Why not just put it to sleep? Not much heat generated when its in sleep mode.

In retrospect, that could have been an alternative. Probably better just to power off, since in sleep mode, it wouldn't have gone through its maintenance tasks. It'd also wake from sleep if the mouse got jostled with traffic through the room.

BTW, great user name!

Mind if I use it for my next band? :)

i leave mine running quite a bit. i put the monitor to sleep, and the computer itself, but its been left running, andit's still fine.

Leopard wakes from sleep to run maintenance tasks
 

I read that leopard does wake from sleep to run maintenance tasks:eek: