alright .. thanks for replying !!
I will summarize what I understood from the previous links :
Hibernate:
>Mechanism:
wipe out every thing u have on the RAM (OS & and any application u r running ) and store them to HDD and turn ur pc off without going through the normal turn off procedure.
>Advantage:
its turn off ur PC so there is no any power consumption.
>Disadvantages:
not really sure , but I will try : use a a lot of HDD space " I saw on my laptop that this feature uses 11.9 GB !! " . In addition, slower load than Sleep mode. And might a system crash after loading ?!
>when to use ? :
when u want save ur work and u aint going to use the PC for several hours.
Sleep :
>Mechanism:
ur PC is almost off ! ACPI keep ur RAM powered so it can keep all ur work on as long as it on the sleep mode.
>Advantages:
Faster load ! as soon as u open the laptop lid , every thing back same as u left them last time !
>Disadvantages:
ur battery in use ! and I understood that it reduces the battery life. And it does not effect the RAM.
>when to use ?:
if u r going continue ur work within few minutes (not taking long time)
ok .. am I right ? correct my information if there is any thing wrong !
thanks