Windows not recognizing and using all of my ram

[failstoomuch]

So i used CPU-Z to make sure all of my ram is in, and it is all 8gb of it. then when i go to computer properties, it only recognizes 6gb and uses 4gb of it. I have an authentic copy of windows 7 professional 64bit. My motherboard is a Gigabyte GA-78LMT-USB3 and according to pcpartpicker it can use up to 32gb

 

[CountMike]

Check msconfig > Boot > Advanced options and Max Memory settings.