20GB of RAM only 3.3GB usable

[eternityx]

A couple of days ago I bought some new Kingston HyperX Blu 16GB RAM (KHX13C9B1K2/16).
When I put them in, it would load the memory up to 3067 and would POST a memory problem.
I tried putting in my old memory with the new memory but it wouldn't boot at all, but when I tried 2 of my old sticks with 1 of the new RAM it would boot fine. The only problem is that windows only reads it as 3GB, but when I check in HWiNFO it says that all 12GB is loaded.

http://i.imgur.com/pJXYKCH.png
http://i.imgur.com/wDUOPXi.png?1

Specs:
Windows 7 Home Premium 64bit
Intel Core i3-550 @ 3.20GHz
ASUS NVIDIA GeForce GTX 660 2GB
(Old Ram) 2 x Samsung 2GB - M378B5673FH0-CH9
DX4840 Motherboard (Store-bought)
Corsair TX850
WD Caviar Green 1TB

NOTE: I am using 64 bit, it looks like a 32 bit problem but this isn't the case.
Edit: I think my motherboard only allows 4GB per dimm slot but why would it be limiting all of the ram just to 3GB?

 

[danny2000]

I can't tell for sure, but it looks to me like your system's board support up to 8 gb of ram, which means 2gb chips per each of the 4 slots.

 

[danny2000]

You need to tell his which exact model of the your 4840 you have; Kingston lists about 6 different models, and all have different specs and limits. http://www.kingston.com/us/memory/search/Default.aspx?DeviceType=2&Mfr=GTW&Line=DX%20Desktop&Model=71575

 

[eternityx]

You need to tell his which exact model of the your 4840 you have; Kingston lists about 6 different models, and all have different specs and limits. http://www.kingston.com/us/memory/search/Default.aspx?DeviceType=2&Mfr=GTW&Line=DX%20Desktop&Model=71575

I have the DX4840-11e

 

[eternityx]

I can't tell for sure, but it looks to me like your system's board support up to 8 gb of ram, which means 2gb chips per each of the 4 slots.

If I was to get a board, what should I get that would support the 2 x 8 sticks?