A question about Hibernation...

Hi everyone, i'm new i here but i read this beautiful forum from a month or two.
I have a question about the hibernation...
I always read that windows 7, as windows Vista, uses the memory to speed up the programs you have already launched, in the installed RAM there is one part that stores this information, and under the resources monitor this RAM is indicated as "Standby".Right?
Well...
i tried to hibernate and resume my system...and all of this information are lost, there's no more "standby ram", and the system start to recreate it every time.
So my question is...
Why during the hibernation windows 7 doesn't store this information on the hard disk?

Thank you for the reply.
I know that with the suspension i can save everything, also the "cache" i am talking about, but suspension needs power to keep the ram operative.
My question was more like "what sense can have not to write ALSO the standby ram to disk during the ibernation?"

Are you sure about that? :S
I think that's not even possible...
Hibernation saves your data on the hard disk, how can they be deleted "after a period of time" if the pc is off??

mborner said:

When you put your PC into hibernation, it will save your open windows for a period of time. If the PC continues into hibernation for an extended period of time, it will close everything and you'll have to reopen all of your work again. (hope you saved your work before you hibernated). Sleep mode is much better. It will keep all of your work open no matter how long the PC sleeps.

You have that completely reversed. Hibernation lasts regardless of the amount of time that passes. Sleep will be lost if the battery (laptop only) goes completely dead.