Windows can't see 4GB out of 12GB

[GreenClick]

I have 3 4GB memory sticks installed. Windows won't see 4GB.

 

[SkyNetRising]

Windows sees your ram. What do you think this means - "Installed memory (RAM): 12.0 GB (7.99 GB usable)"?
One problem I see there is that your ram is operating in 1066mhz mode instead of 1600mhz.
Can you post screenshot from Resource Monitor - memory tab? (physical memory map visible)

 

[Phillip Corcoran]

Windows can see 12GB, that's clearly obvious from your 'System' screenshot

7.99GB is available for running software, the remainder is already being used by hardware.

There is nothing wrong.