Note 4 ( 2 gb useable ) ?!

Hello ! Before 2 days i bought an locked sprint note 4..
the phone was very slow some times .. i tried to check the phone ram ..
after i downloaded an AnTuTu.. they shows that i have 2.7 GB ram and 758 MB free.. anyone can help me with that problem? Thanks ..

Info: note 4 SM-N910P
5.1.1 (32-bit)