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novetan

macrumors 6502
Original poster
Sep 3, 2010
398
10
I hv a 27" iMac 2016 model running on High Sierra. For the last 5 yrs I hv always put to sleep when I retire to bed. 2 days ago it suddenly went black out. Send to a reputable 3rd party repair shop and they diagnosed the power unit kaput. After the repair, they advised try as far as possible shut dn the com every night before I go to bed. This is to allow all the components, circuitry, etc a good rest and to prolong its useable life. And always good to let it completely cool down at the end of the day. And one of the reason why my power unit broke down was because "not enough rest." or probably wear and tear. However upon google search, I cannot find the same reason as the vendor explain. The reason thus far I read was for all the good points if let it on sleep mode, the com will update email, calendar, notes that is carried out on other devices, auto backup on TM, updates, etc. Only one article I came across was there is very little savings in electricity between sleep and shut down. Here's my q:

1) I'm retired and I use it mainly for photoshop and some surfing. Instant updating of calendars , backups, etc is not the most impt for me. I normally do a manual backup as and when I prefer. I'm not worried abt losing my edited photos as they are stored in the clouds when necessary upon my command.
2) I still liked the immediate start up when set to sleep. But if what the vendor said is true, then I think I hv to embrace the longer start up when set to shut down. Its not the few cents savings I'm counting. To replace the power unit was actually quite a hefty sum plus the inconvenience of waiting.

Pls advise what would be your preference if you are in my circumstances? Will the constant sleep mode 24/7 render the parts spoil? This for academy knowledge.

TQ
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,729
12,843
Since I got my first Mac in 1987, I've powered down my entire setup each and every night.

Works for me.

Give it a try...
 

za9ra22

macrumors 65816
Sep 25, 2003
1,441
1,922
It is always problematic to diagnose a particular cause when it comes to a singular failure such as this, but it does not seem probable to me that the power supply would have been likely to fail due to leaving the system powered up but sleeping.

In many instances, failures like this are caused by 'heat stressing', where a system is booted, warms up, runs at mostly constant temperatures until it then cools down again when powered down. Constant 'steady state' running by comparison causes far fewer component failures.

But in reality, most Macs in sleep mode use very little power, so they cool down anyway. Likewise though, this means relatively little difference in the stressing of components between powering up/down every day, and leaving the system running 24/7.

Systems - electronics in general since the end of vacuum tubes/valves - simply don't need 'a rest' in their operating cycles, which is, I suspect, why you can't find anything matching the repair shop's explanations when searching Google.

In my experience, systems that are left to sleep are no more prone to fail than systems that are powered down. Their energy use is a bit higher of course, but modern Macs, including a 2016 iMac, don't use much power in sleep, so it is largely a matter of personal preference.

I would not be inclined to attribute a power supply failure to anything other than a simple failed component however, and I wouldn't change how the system is used in this sort of situation because of it. I'd pick whatever working and use practices suit you best.
 

novetan

macrumors 6502
Original poster
Sep 3, 2010
398
10
It is always problematic to diagnose a particular cause when it comes to a singular failure such as this, but it does not seem probable to me that the power supply would have been likely to fail due to leaving the system powered up but sleeping.

In many instances, failures like this are caused by 'heat stressing', where a system is booted, warms up, runs at mostly constant temperatures until it then cools down again when powered down. Constant 'steady state' running by comparison causes far fewer component failures.

But in reality, most Macs in sleep mode use very little power, so they cool down anyway. Likewise though, this means relatively little difference in the stressing of components between powering up/down every day, and leaving the system running 24/7.

Systems - electronics in general since the end of vacuum tubes/valves - simply don't need 'a rest' in their operating cycles, which is, I suspect, why you can't find anything matching the repair shop's explanations when searching Google.

In my experience, systems that are left to sleep are no more prone to fail than systems that are powered down. Their energy use is a bit higher of course, but modern Macs, including a 2016 iMac, don't use much power in sleep, so it is largely a matter of personal preference.

I would not be inclined to attribute a power supply failure to anything other than a simple failed component however, and I wouldn't change how the system is used in this sort of situation because of it. I'd pick whatever working and use practices suit you best.
TQ very much for the gd insight and detailed explanation. Will I run a risk in sleep mode during thunder storm or lighting. We may already sound asleep. I don't hv a UPS unit.
 

BrettApple

macrumors 65816
Apr 3, 2010
1,137
483
Heart of the midwest
I own a 2007 iMac that has lived nearly it's entire life powered on, be it in use or in sleep mode. We also have a 2009 iMac at our church that runs the lighting system and has over 80,000 power on hours, according to the SMART stats on it's factory drive and the display that's starting to yellow out due to age/use. So they are certainly capable of going very long term powered up and in sleep mode.

Sometimes crap happens though and a component fails, but I don't think it's due to misuse most of the time. In fact the church I worked at had two identical 2010 Mac Pro towers in the same location sitting next to each other for livestream use and encoding on the fly. Purchased at the same time, used mostly on the weekends powered off when not in use. One had the PSU go out, the other did not. No change in use as they ran in parallel. Just an oddball component failure.

The only iMac PSU I've had die was our 2008 iMac, and only because it got hit by lightning through the ethernet port during a storm. Swapped that out and everything else remained OK surprisingly.

I'd agree with za9ra22.
 

novetan

macrumors 6502
Original poster
Sep 3, 2010
398
10
I own a 2007 iMac that has lived nearly it's entire life powered on, be it in use or in sleep mode. We also have a 2009 iMac at our church that runs the lighting system and has over 80,000 power on hours, according to the SMART stats on it's factory drive and the display that's starting to yellow out due to age/use. So they are certainly capable of going very long term powered up and in sleep mode.

Sometimes crap happens though and a component fails, but I don't think it's due to misuse most of the time. In fact the church I worked at had two identical 2010 Mac Pro towers in the same location sitting next to each other for livestream use and encoding on the fly. Purchased at the same time, used mostly on the weekends powered off when not in use. One had the PSU go out, the other did not. No change in use as they ran in parallel. Just an oddball component failure.

The only iMac PSU I've had die was our 2008 iMac, and only because it got hit by lightning through the ethernet port during a storm. Swapped that out and everything else remained OK surprisingly.

I'd agree with za9ra22.
TQ for taking time to explain.
 
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