Extremely slow boot after Hybrid Sleep

dbmaxpayne · 10 May 2011

Hi,

I've got a very strange problem.
I use Windows 7 Pro x64 in my Car PC.
Hybrid Sleep is enabled, because my CarPC-PSU only keeps up the 5V rail for 18 Hours. After that the power is shut down.
When I wake the PC from standby (within the 18 hours), everything works fine. Windows responds within a few seconds.
BUT: If the PC has been put to standby and the PSU shuts down the 5V rail, the startup from hybrid sleep/hibernate is extremely slow. It takes approx. 5 minutes before I can use Windows again.
What's strange is: When I put the PC to sleep/hibernate manually and boot it up again, everything is MUCH faster. Normal hibernate boot I'd guess.
Only when the PC initially was put to hybrid standby and power cutted off it boots that slow.

I can replicate the same behaviour on my Desktop PC.
Boot from Standby: Really Fast
Boot from manual Hibernation: Normal
Boot from Hybrid Standby atfter PowerOff: Extremely slow

What is causing this? And how can I fix this?

Thank you in advance.

Best regards
Mark

kronckew · 10 May 2011

the long answer:

hybrid sleep is a combination of the normal in-ram sleep (S1 or S3) and the full hybernation (S4) where the contents of ram is written out to your hard disk (hyberfil.sys). it is a fairly slow method of finishing with your pc as well since it has to write the ram to hard disk.

in normal in-ram sleep as long as you have power on the pc it will awake quite rapidly as it just renews the pointers to the existing ram, and wakes up the peripherals. in normal sleep if you lose power it has to do a full cold boot when the power is renewed.

in hybrid mode with power, it awakes in normal sleep fashion. if you lose power in hybrid sleep mode, on startup it reads the hyberfil.sys disk file ram image created on shutdown back into memory.

this, depending on your ram size and disk speed, can take longer than a cold boot as it reads in not only the OS but all the active apps, and their ram contents at the time of last shutdown.

i disable hybrid mode (and hybernation) for this reason as i'd just as soon start over if it loses power.

it's up to you if the extra boot time is worth it or not. i ensure i save any open docs, or images before i go to standby or shut down. justincase.

and the short answer is: your system is acting as designed.

dbmaxpayne · 10 May 2011

Hi and thanks for your answer.

I know the differences between in-ram sleep and full hibernation.
Unfortunately my problem is like this:

manual in-ram sleep: Very fast boot (few seconds)
manual hibernation: normal hiberfil.sys-reading boot (approx. 30 seconds)
hybrid mode without powerloss: Very fast boot (few seconds, like in-ram sleep)
hybrid mode with powerloss: Extremely slow boot (approx. 5 minutes)

I don't think that this is the norma behaviour, is it?

Thanks
Mark

kronckew · 10 May 2011

yes, that is normal behavior. as i noted the hybrid mode with power loss has to read the entire ram contents off the hard disk. this is slow. without power loss it should take seconds. with power loss it might take a minute or more.

the only way to ensure it always comes out of standby fast is ensure the power is NOT lost, ie. it must supply your ram it's 5 volts longer than 18 hours if that is your normal down time. how you accomplish that in your system i do not know, you might need to contact the supplier...

if it were possible to save the hyberfil.sys to a solid state device, an SSD or USB3 thumb drive, it might speed things up a bit. would depend on the details of your system...hyberfil.sys must be on the system drive, apparently, so it would be difficult.

p.s. - how big is your hiberfil.sys & your ram size? it may be possible to make it a bit smaller (and thus load faster) min. is 75% max is 100% of your ram size.

dbmaxpayne · 10 May 2011

Hey,

thanks again for your answer.
Unfortunately I think were talking at cross purposes^^

When I hibernate the PC manually (no hybrid mode, just the real hibernate mode) AND cut the power (I do this on my Desktop in the evening), the hiberfil.sys is also read back into memory, but this works quite fast.

manual hibernation: normal hiberfil.sys-reading boot (approx. 30 seconds)

Only when I put my PC into hybrid standby/sleep, cut the power and then reboot it is that slow (approx. 5 minutes).

BTW: RAM-size is 2048MB and about 1gig is used.

Mark

kronckew · 11 May 2011

ah, well. i'm about out out of ideas. if it works OK on the desktop when you personally cut the power (unplug?) but works differently from the same system with the CarPC-PSU i give up. is the car pc a different system or the same as the desktop? if different are the specs different? what happens if you manually power off (unplug) the car pc as you do with the desktop?

one last:

the only software control for the hibernation file is the powercfg.exe app. the default size of the file is 75% (win7 does normally try to do some zip-like compression so 75% theoretically could hold a whole image) of your ram in win7. this can be adjusted up to 100%. you might want to try 100 as it's possibly too small to hold a full ram image if it is only 1 gb out of 2 (50%). you could also try smaller but it might give errors & require a cold boot.

from an admin. command prompt the syntax is

POWERCFG -H -Size <size>

where <size> is a number from 0 to 100 - without a % sign.

offer · 23 Jul 2014

I don't believe that the problem has to do with power being disconnected while in hybrid-sleep. I worry rather that it is a random problem (forgive me, original poster, maybe the randomness led you to believe it is a power-disconnect issue). Therefore, I don't think the root cause is as described by the responder. I also have a similar problem and I would anxiously love to hear explanations or maybe solutions. (I could be wrong of course and there could be indeed two different problems. In that case, I apologize for diverting the hread way from its original post.)

I have a Windows 7 Home premium 64 bits installed on a desktop(!). Since I installed it (over a year now) I have experienced AT TIMES extrememly slow resumes from hybrid sleep. 95% (or even 98%

) of the times, the resume proceeds in its normal sleep, but occassionally it takes 5-7 minutes for the system to become fully-ready.

I've been spending a lot of time trying to find patterns or any other clues as to when it happends and when it's not. Nothing, and I sort of lost hope. My only useful addition to this thread is that my desktop PC is connected thru a UPS and I've verified, it works 100%. It never happened to me that I lost my power on my PC due to a UPS malfunction, so I conclude that the reason for the slow resumes cannot be power outages but lies elsewhere.

Anyone has a guess?

offer · 23 Jul 2014

Forgot to mentioned some points which may be relevant:
1. I don't use SSDs, just a regular (fairly speedy) HD (1 only)
2. When I wrote "takes long time" I meant much longer (maybe 10/15x) that resuming from old-fashioned hibernate, which I guess it means that the problem has nothing to do with reading the hiberfil.sys file.
3. In the fist phase of the resumption (for 60-90 seconds) only the power LED is on. No HD activity and no screen
4. Finally, at times, after the phase described in #3 above, the machine seems to go thru a power cycle (quick one) and then HD activity starts and the resumption behavior start to look more normally (albeit extremely slow)