2 Newbie Questions

[Stryder]

Since I have been a windows user for about 10+ years, I have always maintained it inside and out. I custom buit 5 of my own computers, with that being said, I use to open them up, clean every little inch of the internal stuff ( Processor fan, all other fans, etc )

In my imac, Is this possible? Doesn't this collect dust on the inside?

All I have come across online was a guy wiping the screen.

Now my 2nd question.

Is it suggested to leave the imac on or off? Does it even make a difference?

Thanks...

[cwtnospam]

1) The new iMacs are built very much like laptops inside. When's the last time you opened one of those and cleaned out the insides?

2) That depends on how long you use it during the day/evening. If it's likely to be used during 18 hours of the day, shutting it down for the other six might not be beneficial. If it's only used for 8, then shutting down is probably a good idea.

[Stryder]

lol I see what you mean, you're right about laptops, I didn't think about that lol

Well, as far as leaving it on, so you're saying it really doesn't make a difference " overall? "

Thanks for the quick reply.

[iampete]

Quote: Originally Posted by Stryder . . . Is it suggested to leave the imac on or off? Does it even make a difference? . . .

There are two distinct issues here. One is lifetime of the computer, the other is "wasting energy".

Under standard circumstances, power ON/OFF state transitions are arguably the most stressful events experienced by electronic devices. Naturally, the degree of stress depends on many factors and the specific type of component.

Since we're no longer talking about tube-type technology, the issue is not so much with the individual elements (chips), etc.; rather, it is with the connections of the chip itself, circuit traces, solder joints, etc. Countless hours and dollars have been spent by many organizations to determine useful "rules of thumb" regarding proper operation of devices in terms of "x ON/OFF cycles represent y lifetime hours". As of a couple of years ago, to the best of my knowledge, there was no study result that various experts in the field agreed was definitive. Although one can find opinions that recommend never turning things off, the most commonly held opinions that I've encountered in the aerospace industry are that one ON/OFF cycle is equivalent to hundreds of hours of operational lifetime.

As far as the "wasting energy" issue is concerned, that's up to your wallet and your conscience.

[styrafome]

Would sleep mode count as an on/off cycle or not? The reason I ask is because technically it is still powered, but the level is so low that waking it creates a significant boost in current.

I'm only asking about whether this is a significant wear issue electrically. Even if it was not, waking from sleep probably still creates thermal stress.

Having said all that I am the type to shut down or sleep a computer if I expect it to be unused for over half of a 24-hour day. Stuff hasn't been breaking, so I suspect this is well within a normal use case. In other words, if companies are designing components expecting that consumers will turn them off or sleep them regularly (as Apple sets Macs to sleep on inactivity by default), then maybe a computer's life will not be shortened so much that you'd be affected before you upgrade to the next model within 3-5 years.

[dandj]

Solid state devices are most reliable when they operate within their rated specs, and in a stable thermal and electrical environment.

Sleep mode changes both, so yes, sleep mode (or screen blanking) must be considered as an on/off cycle, but not as bad as shutting down. Shutting down is worst than sleeping since power supplies are shut down completely and they are usually the most stressed components in any electronic equipment.

Electronics is incredibly reliable if left alone, most failures will be in electromechanical items, like connectors, switches and moving parts (disk drives, mice, keyboards).

My iMac gets incredibly hot while working, due mostly to the LCD screen, and cools down totally if the screen is blanked, or asleep. But it also saves a heap of power either way (250W+ down to ~2W) so I blank the screen when I leave it and accept the small risk of thermal shock when it wakes up.

[iampete]

Quote: Originally Posted by styrafome Would sleep mode count as an on/off cycle or not? The reason I ask is because technically it is still powered, but the level is so low that waking it creates a significant boost in current. . .

I don't really know how to answer that.

What I've been told is that the issue of greatest concern is that thermal effects of OFF/ON cycles result in the "normal" microscopic imperfections of solder and other connective joints getting larger and larger with each cycle until they deform, break, whatever. If the currents used for sleep keep the temperature significantly above the ambient OFF state temperatures, one would think that the thermal effects of a "sleep state" to full ON would be significantly less than from an OFF state to ON.

However, to the best of my understanding, some devices implement "sleep state" in such a manner that some components are totally unpowered while others have a smaller than normal current flow, e.g., for older picture tube type TVs, there was current flow through some tube elements only in order to eliminate long warm-up times, but the other components were unpowered. I don't know how sleep works in computers.

I've been involved in projects where the vendors of some assemblies indicated that a sleep/ON cycle was to be counted as less than a tenth of an OFF/ON while for other assemblies a sleep/ON cycle was counted as one-half of an OFF/ON cycle.

Since the effects of OFF/ON and sleep/ON cycles are undoubtedly different for different types of chips, different circuit elements, different components, etc., it's difficult to come up with a "right" answer for something like a computer.

Quote: Originally Posted by styrafome . . . companies are designing components expecting that consumers will turn them off or sleep them regularly (as Apple sets Macs to sleep on inactivity by default), then maybe a computer's life will not be shortened so much that you'd be affected before you upgrade to the next model within 3-5 years.

I expect that you're correct here. Given that turning a computer off and on once a day will result in just over a thousand cycles over three years, it's probably a relatively small likelihood that a failure attributable solely to off/on cycles will occur during that time.

[Stryder]

Holy crap did this get technical.

I just wanted to know if it mattered to leave it on or should it be turned off lol

I can assume from this that I should leave it on and if anything and maybe just blank out the screen for cooling.

Thanks aha

[iampete]

Quote: Originally Posted by Stryder . . . I can assume from this that I should leave it on and if anything and maybe just blank out the screen for cooling. . .

Actually, all I was trying to point out is that there are a lot of things to consider that make a definitive answer to the original question impossible. There is probably nothing "wrong" with the strategy cwtnospam identified in his post, just as there's probably nothing "wrong" with never turning it off.

For whatever it's worth, my system is set up to put the hard disks to sleep whenever possible and to go completely to sleep after an hour of inactivity. Also, whenever I know I'm not going to use it for more than a day, I shut it off completely. So far, so good.

[cwtnospam]

If you do leave it on all the time, have it do something useful, like folding@home. At least then the energy is being used to combat disease.

[Photek]

Quote: I just wanted to know if it mattered to leave it on or should it be turned off lol

when your not using it... turn it off.

[Stryder]

lol cetnospam & photek. I never thought of that. ahaha

I basically asked because when searching I saw some people get technical about unix and how it benefits from being on more so then on and off.

I prefer to leave it on because what good are the screensavers & wallpaper when they can't be seen? Especially on a 24 inch. :-)

[styrafome]

Quote: Originally Posted by iampete Given that turning a computer off and on once a day will result in just over a thousand cycles over three years, it's probably a relatively small likelihood that a failure attributable solely to off/on cycles will occur during that time.

Thanks for your insight on this that you backed up with others' viewpoints. This confirms what I have been thinking, that even though power cycling is not good, the negative effects are likely to be outweighed by the benefits of saving electricity (lower costs, lower power demand by society).

Laptop users should note that this debate is not something they have control over, because typical laptop users cannot operate in a full wake state 24/7, since they have to sleep or shut down before transporting it. A typical laptop user will put their computer through several power and temperature cycles per day, as the unit is slept and woken at home, at work/school, in each class/meeting (could be several times if moving between desk and meetings all day long), and back home. When unused long enough, it cools down, imparting thermal stress with the next wake.

Now that millions of people around the world put their laptops though this every day, it's interesting to note that we aren't seeing mass laptop deaths traceable to power cycling. A lot do die, but not enough to cause general alarm. They can then be assumed to be built to take the kind of power and thermal cycling treatment that IT pros would condemn as severe abuse.

This is not a license to put your Mac through excessive off/on cycles. I do try not to do them any more than is reasonably necessary.

Quote: Originally Posted by Stryder I basically asked because when searching I saw some people get technical about unix and how it benefits from being on more so then on and off.

This could just be the old guard Unix talking, where things like cron jobs ran in the middle of the night so you better leave it on all the time. But, Macs have special routines now so that if the Mac was off at the usual Unix overnight maintenance hours, OS X will notice and Unix maintenance jobs will still be run and not missed. Apple may have added this to OS X because again, with portables being the bulk of sales, almost nobody leaves their laptop on overnight.

Quote: Originally Posted by Stryder I prefer to leave it on because what good are the screensavers & wallpaper when they can't be seen? Especially on a 24 inch. :-)

Yes, it's cool. However...and this could start another debate...there is the question of whether you want to burn up all your LCD backlight lamp life on a screen saver.

There are two schools of thought here. One is that, like electronics, a fluorescent bulb will last longer if you don't switch it on and off all the time. So you can just leave it on. The other school says your lamp uses up its lifetime hours the more you have it on, so better not to leave it on when not in use.

I set mine to go black after an hour or two. That way, if I'm around, it won't cycle off while i'm around. If I haven't touched it in a couple hours, I'm probably gone for a while and it should go black.

Most consumers may not have to worry about this, but if you are a pro with a really expensive color-critical monitor, you may not want the bulb to die or become too dim to calibrate sooner than it needs to. Also, backlight bulbs seem to last longer than they used to a few years go.