Cant use full amount of installed RAM

SuhasTS

Honorable
Jan 11, 2014
45
0
10,540
Hi , I have an AMD FX 6300 , Asus M5A78 motherboard , no graphics card installed , a 250W PSU and a WD 500GB Harddisk.
I have 2 RAM sticks plugged into my motherboard, a 4 GB and a 2 GB (both DDR3). Im a running a Windows 8.1 (32bit ) system.
When i check PC info, Its shows 6GB RAm installed , but only 3.25 GB RAM usable. Is it because Im running a 32 bit system? How can I utilized RAm to full extend?