I am confused concerning the maximum  memory for the Inspiron 580. On the Dell web site, it states 8 GB is the maximum (4x2B). 

Reading in another post I saw that this limit seems surmountable. 
I state that I have installed windows professional 64 bit.
Now I have 3 modules of 2GB for a total of 6 GB.
I would like to install an additional module to 8 GB for a total of 14 GB.
I can do that?
There are problems because the modules are not paired two by two?
Thank you