windows server 2008
go to
C:\Program Files\Openfire\bin (openfire path)
open three files using notepad
openfire.vmoptions
openfired.vmoptions
openfire-service.vmoptions
and put this
-Xms265m
-Xmx512m
where 265 mega will be minimum memory for openfire
and 512 mega will be maximum memory for openfire
you can change this values as you need
then restart openfire and check the memory
Note:
don't increse memory more than RAM memory
