ddr3 ram copmtability

[sac8444]

I have 1stick 4gb ddr3 adata ram i upgrade but 4gb still usin and i want buy another 8gb ddr3 is possible this ram total 12gb and this is run my motherboard is asus m5a78 lx v2 please answer me iam confuesed in this pairing

 

[salerhino]

You have 2 slots so 4GB + 8GB should be OK but no one can guarantee that sticks from not the same kit will work together.