[SOLVED] Only 7.99GB of my 16GB RAM usable. Help!

[confused676]

I'm currently running with the following specs:

OS: Windows 8.1 Enterprise 64bit machine
Motherboard: MSI 990fxa-gd80 v2
Processor: AMD Phenom II X4 980 3.70GHz
RAM: 4 sticks of 4GB Corsair Vengeance DDR3

The following is a screenshot of what it tells me when I look at my RAM in the PC Settings:
https://i.imgur.com/VJtJnEO.jpg

Any help would be greatly appreciated! Thanks in advance.

 

[rookieGamer]

u didnt get 4 sticks in a kit did you ?

 

[confused676]

Yes, they were ordered together and share the same manufacturer and model ID to ensure compatibility.

 

[rookieGamer]

Yes, they were ordered together and share the same manufacturer and model ID to ensure compatibility.

if they didnt come as a kit then there is NO guarantee they will work together even same brand and same speed.
remove all of them and add them one by one..add one boot up and see which one dont show up