ONE STICK of RAM Corsair Vengeance
8 gig (2x4gig) 1600 MHz 1.50V ver 2.12
Not sure what your "ONE STICK" refers to. The "(2X4gig)" would mean 2 sticks of 4Gb RAM = 8 Gb so if you only installed 1 stick of 4Gb RAM the system is reporting correctly and you only have 4Gb.
If you have 4 memory slots on your motherboard make sure that you have your RAM modules in the correct spots so that they can run in dual channel. They typically are color coded, however yours are not, so you will want to put both sticks in the dim1 and dim2 slots (should be labeled on the mobo).
ONE STICK of RAM Corsair Vengeance
8 gig (2x4gig) 1600 MHz 1.50V ver 2.12
Not sure what your "ONE STICK" refers to. The "(2X4gig)" would mean 2 sticks of 4Gb RAM = 8 Gb so if you only installed 1 stick of 4Gb RAM the system is reporting correctly and you only have 4Gb.
What's the Corsair part number?
Sorry, thats just what was on the label of the stick, I only have one physical stick that has "8 gig (2x4gig) 1600 MHz 1.50V ver 2.12" on its stickers.
Since you only have one of them installed, you only have 4GB of memory. Did you install yourself, or did someone do for you? Where did you get this memory from?