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Any point to sleeping computer with an SSD??

Tumbleweed666

Tumbleweed666

macrumors 68000
Original poster
Mar 20, 2009
1,761
141
Near London, UK.
My iMac has a SSD internal disk.

I have an app that has some problems with sleep behaviour, in that its not telling the mac to keep awake when its running (since OSX changed how that works, as I understand).
So, a temporary or longer workaround is to tick "prevent computer from sleeping when display is off" then the computer never sleeps and the app has no issues.
Given its an SSD so there arent any moving parts, is there any use to sleeping it anyway?
TIA
 
thedeske said:
Ever run the numbers to see what it really costs?
140w vs 1w etc. Average hours it sleeps?
Click to expand...
No I haven't. My iMac has a hard drive and not a SSD so I think it's good that it sleeps while I sleep. Or during the day when I'm gone most of the day.

Even it it only saves a few cents night, it adds up. And if I forget to sleep the computer I don't worry about it.
 
Tumbleweed666 said:
My iMac has a SSD internal disk.

I have an app that has some problems with sleep behaviour, in that its not telling the mac to keep awake when its running (since OSX changed how that works, as I understand).
So, a temporary or longer workaround is to tick "prevent computer from sleeping when display is off" then the computer never sleeps and the app has no issues.
Given its an SSD so there arent any moving parts, is there any use to sleeping it anyway?
TIA
Click to expand...

Other than power usage already mentioned, the only thing I can think of is by not sleeping the fans are running 24/7, so I suppose that would contribute to fans dying earlier and also sucking more dust into the machine. That said, we don't seem to see many reports of fan failure, so who knows if it is enough of a difference to matter.
 
Weaselboy said:
Other than power usage already mentioned, the only thing I can think of is by not sleeping the fans are running 24/7, so I suppose that would contribute to fans dying earlier and also sucking more dust into the machine. That said, we don't seem to see many reports of fan failure, so who knows if it is enough of a difference to matter.
Click to expand...

Any one who ever owned a room air cleaner knows how nasty the filters get in short order. We forget the computer is a small version of just that, without the filters! I and 2 others I know are famous for letting dust build up and shocked at how much sludge we see when we finally get off our butts and open up for a friendly blast of air. I've yet to be convinced that a small percentage of downtime(sleep) makes much difference for this or power. Then again, it is a few bucks, so to each his own ;)
 
thedeske said:
...
I've yet to be convinced that a small percentage of downtime(sleep) makes much difference for this or power.
...
Click to expand...
If you look at 7 nights sleep and 5 work days. You're looking at sleeping the computer over 50% of the time. This should make a difference ot how much gunk the fans suck in. And will save some money on electricity and if you live in a hot location will also save money on air conditioning.
 
thedeske said:
Ever run the numbers to see what it really costs?
140w vs 1w etc. Average hours it sleeps?
Click to expand...
Apple publishes environmental reports on its products:

http://www.apple.com/environment/reports/

The current 27" iMac uses about 78W with the display on, 20W when the display is off, 1W in sleep mode, and 0.25W powered down (still plugged in).

If my math is correct ( 365 x 24 x 78W ) / 1000 = kWh per year. At $0.14 per kWh, that's about $96 in annual electricity costs for a Mac that's always on (and the display never dims). Now if you ran your computer 6 hours with the display on, 2 hours with the display off, and let it sleep the other 16 hours, your annual electricity cost would be around $26.

Apple has put a significant effort into optimizing power consumption.

It's probably a wasted effort doing a detailed power consumption analysis with a Kill-a-Watt meter, spreadsheets, etc. Use your computer when you need to use it, let the default power settings put the computer to sleep when you're busy doing something else. Turning off your computer isn't much of a cost savings over sleeping.
 
Thanks guys, less dust being sucked in is probably the best benefit for me then, I think as my app runs to a schedule once a week I may have to cook up a script that wakes the iMac in time for the app, then sleeps it again a few hours later at a time I expect the app to be finished.
 
The only time I've had issues with any of my SSDs is when I let them sleep, so I never let my computers sleep, If I'm awake, they should be too.
 
AFAIK the stress of switching on and off is one of the key factors that leads to decreased life, due to temperature fluctuations, electronics does best if left in a steady state.
 
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