ok ill do that, what numbers do you use (latncies?), and voltges?
You don't want to clock down the existing ram you have, and you don't need to add better ram than your system will use with what you have.
Same voltage, same latencies, same speed. If you can get the same brand that's a bonus, but should not be necessary.
The easiest way is to use a GSkill part/model # like this example: F3-12800CL9D-4GBNQ
Look on one of your ram dimms and get the number and buy that.