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Andrey84

macrumors 6502
Original poster
Nov 18, 2020
268
224
Greater London, United Kingdom
While checking on my SSD's health, I was surprised to see the Power Cycle Count of 70,619 yesterday. I was even more surprised to see it increase by 21 to 70,640 today, even though total pick-ups for today and yesterday were 9, and I've disabled 'put hard disks to sleep when possible' yesterday.

It's a Mid 2015 15" MacBook Pro 11,4 (i7/16/512).

As you can see, I don't think the disk sleep setting has any effect, as I got 21 new power cycles still over the 24 hours. 21 appears to be very close to the daily average for power cycles over the lifetime of this machine: 21 x 365 x 8.5 = 65,152.5.

I expect it to have been used professionally until 2019, when I bought it, and since then I only used it casually (not every day).

I know this statistic probably doesn't really matter, and the laptop will easily live another 5-7 years, to the point of becoming fully obsolete, and SSD will still be fine. However, this SMART indicator is showing 30%, which is worrying.

Why does it power up and down so often?

Do you have any ideas how to reduce the daily increase in power cycle count?

Screenshot 2024-01-07 at 15.46.34.png


Screenshot 2024-01-07 at 16.02.15.png
 
Last edited:

ignatius345

macrumors 604
Aug 20, 2015
7,564
12,905
You're worrying about the wrong metric. Watch ID 178, your Wear Leveling Count. That's at 89%, indicating that in the 9 years this machine has been in operation it's doing absolutely fine.

I have a feeling these power cycles are possibly related to the Energy Saver (or Battery) setting for "Put hard disks to sleep when possible". Seems like putting a drive to sleep to save power might count as a "power cycle"?
 
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Andrey84

macrumors 6502
Original poster
Nov 18, 2020
268
224
Greater London, United Kingdom
You're worrying about the wrong metric. Watch ID 178, your Wear Leveling Count. That's at 89%, indicating that in the 9 years this machine has been in operation it's doing absolutely fine.

I have a feeling these power cycles are possibly related to the Energy Saver (or Battery) setting for "Put hard disks to sleep when possible". Seems like putting a drive to sleep to save power might count as a "power cycle"?
Ok, thank you. Do you think the SMART setting is showing this metric as 30% because these percentages are still based on mechanical disks?
 

ignatius345

macrumors 604
Aug 20, 2015
7,564
12,905
Ok, thank you. Do you think the SMART setting is showing this metric as 30% because these percentages are still based on mechanical disks?
That I do not know. Someone more knowledgable will have to chime in on that. It's worth looking into, but I think the Wear Leveling Count is the one to really watch.
 
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WilliamG

macrumors G4
Mar 29, 2008
10,006
3,893
Seattle
Ok, thank you. Do you think the SMART setting is showing this metric as 30% because these percentages are still based on mechanical disks?
I’d guess so. I don’t think there’s any data out there on cycle counts on an SSD or if there’s any point to them.
 
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