[Erythros]

There is a difference between internal Storage and your External Storage Card.
When you install programs the options are "device" or Storage Card (FLASH MEMORY or ROM), this is SLOW memory used for storing stuff even with no power.
If you install many programs on top of your running OS that are running in the background then you will use up Program memory(RAM MEMORY), this is FAST memory used for running stuff. The more stuff you have running the more RAM you use and therefore the more power is needed.
If you take many photos with your phone, the default folder is your internal phone Storage (ROM).
You can install Programs to the Storage Card (Micro SD), but running them uses your Program memory(RAM)
Go to SETTINGS--> DEVICE INFORMATION and lookup how much memory you have used under these categories.
The Phone OS is Stored in ROM, but run in RAM.
If you see your device running sluggish, you should trim your contact list if possible and delete unnecessary SMS and email from your device.
Just as a HARD RESET seems to bring a dying phone back to life this will help as well.
You cannot repartition the different types of memory (Correct me if I am wrong) because they are different types of memory.