M5A97 Ram Problem!

[Smokeybars]

Trying to install 4gb ram into my M5a97 Asus motherboard so I'll have 8gb in total.

Ram is corsair 1333mhz DDR3.

When I go into Windows saying only using 3.9 of it. Using 64bit Windows7

In North Bridge settings of BIOS it's reading both sticks of ram but windows isn't?

Help!?

 

[Calvin7]

Mixing RAM modules that did not come in a kit together may be incompatible together. The module may also be defective.