no.
its no problem at all.
if you mean that the hibernate file takes up 3gb, yes, it must be the size of the ram!
windows only seems to write what is in memory, so it doesn't write 3gb each time, i hibernate with 2gb laptop and 4gb pc setups all the time and it doesn't take that long at all.
if you are starved for space turn on ntfs file compression in most directories on c: just right click..go to properties..let it crunch it down. performance difference on a modern system isn't all that great. in anycase..upgrade your drive if its that tight!! ccleaner is a free program to cleanup temp files and other muck wasting space. hotfix remover is also another one that removes the uncessary uninstalls for all the windows patches you accumulate over time. couple hundred megs atleast, its no loss unless you plan on uninstalling windows updates for some odd reason.