Need Ram advice (2 different types)

[Imabigmac]

would there be a problem if I were to add 2 sticks of 2GB of ram to my current 8gb to make a total system capacity of 12gb?

What are chances of incompability if both the voltage and cas latency are different between the 4gb set and my original 8gb set?

I know the higher speed would get down clocked but, will not having the same latency be another issue? On top of other issues.

[Archangel1994]

I have it right now. Just make sure they are equal speeds and voltage. The latency/frequency will adjust itself to the slowest I think