If I have two DDR3-1330 (2GB each, 2 mobo slots), can I toss one out and buy add. 8GB?

[Paul19-95]

Here's my situation.
I have mobo with 2 slots for DDR3-1330.
Can I buy another stick of 8GB, remove one 2GB to free up the slot, and have practically 12 GB of RAM?
I've read somewhere that some memories work dually and thus I would decrease their performance.

Any help appreciated.

 

[Tradesman1]

What mobo? Not all mobos support 8GB sticks, also what CPU?

 

[Paul19-95]

What mobo? Not all mobos support 8GB sticks, also what CPU?

foxconn h55mxv lga1156 socket, i3 540

 

[Tradesman1]

1156 doesn't support 8GB sticks