2.47gb usable, why?

Hey, My friend recently brought a pc and built it, the pc is running fine but out of the 8gb of crucial ballistix 1866mhz memory only 2.47gb is usable, i have already advised him to reinstal windows but im not sure if that is the problem or not. any help? thank you

 

 

I had a similar problem, the cause was the ram not being installed correctly. Remove the ram and re-seat it, sometimes, you really have to jam it in there. Also, make sure he has a 64 bit os

the problem was the os he had installed 32-bit so he upgraded to 64-bit now has 7.46gb usable, thanks for your input

 

 

That's still not quite right, all 8gb should be useable.

Intergrated graphics use ram