turned off sleep image (2gb reclaimed) - a bit worried

[sir. mac]

Just followed these instructions here (http://forums.macrumors.com/showpost.php?p=4897099&postcount=16) to turn off the sleep image and let the machine write to memory in sleep mode. This reclaimed 2gb on my MBA and I was happy as a puppy :p

Now whenever I let the machine sleep, every few minutes the logo on the back flashes up for a short while, like it´s waking up. Is this supposed to happen?

Also, could there be some permanent disk damage if the battery runs out while the machine is in sleep mode now?

[Salty Pirate]

Just followed these instructions here (http://forums.macrumors.com/showpost.php?p=4897099&postcount=16) to turn off the sleep image and let the machine write to memory in sleep mode. This reclaimed 2gb on my MBA and I was happy as a puppy :p

Now whenever I let the machine sleep, every few minutes the logo on the back flashes up for a short while, like it´s waking up. Is this supposed to happen?

Also, could there be some permanent disk damage if the battery runs out while the machine is in sleep mode now?

I let the machine run out of battery to see what would happen and the machine shuts down when 1 minute was left. I shut the machine and charged it, to my surprise I opened it and it came up just fine.

As for the flashing, that is not normal. Have you re-booted and tryed it or re0-set the smu or pmu or whatever it is called? The other thing you could try is create a test account, put the machine to sleep and see if the behavior manifests itself. If it does, I would say it is apple store time.

[BryanLyle]

Once you make this change, can you go back to hibernate mode 3 ? If so, how do you do it?

[clayj]

Once you make this change, can you go back to hibernate mode 3 ? If so, how do you do it?Just run this command in Terminal:

sudo pmset -a hibernatemode 3

[sir. mac]

Seems fine after the reboot. Good to hear that it won´t melt my machine, thanks for the info :)

[raremage]

FYI there is a nice article on how sleep mode works here (http://www.macworld.com/article/53471/2006/10/sleepmode.html).

[sir. mac]

Thanks! But now the battery seems to drain more during sleep, anyone else notice this or is it just my imagination? Will come back later with some tests on this.

[sir. mac]

yup, seems like it drains more battery whence in mode-o:

# 0 - Old style sleep mode, with RAM powered on while sleeping, safe sleep disabled, and super-fast wake.
# 1 - Hibernation mode, with RAM contents written to disk, system totally shut down while “sleeping,” and slower wake up, due to reading the contents of RAM off the hard drive.
# 3 - The default mode on machines introduced since about fall 2005. RAM is powered on while sleeping, but RAM contents are also written to disk before sleeping. In the event of total power loss, the system enters hibernation mode automatically.

[Spievy]

yup, seems like it drains more battery whence in mode-o:

# 0 - Old style sleep mode, with RAM powered on while sleeping, safe sleep disabled, and super-fast wake.
# 1 - Hibernation mode, with RAM contents written to disk, system totally shut down while “sleeping,” and slower wake up, due to reading the contents of RAM off the hard drive.
# 3 - The default mode on machines introduced since about fall 2005. RAM is powered on while sleeping, but RAM contents are also written to disk before sleeping. In the event of total power loss, the system enters hibernation mode automatically.

Very interesting, I had no idea. I am assuming this works on all intel macs?

[raremage]

I wonder why it drains more in mode 0 versus mode 3?

Other than the power to write the memory to disk initially, i wouldn't expect that - I was under the impression the functionality would be identical.