I have a Dell Inspiron 1525 that I'm upgrading for a family member and I was going to buy more ram. The system uses DDR2-667 PC2-5300 SODIMM, do I need to keep the sticks in pairs of the same size and brand etc... Or does this not really matter....Sorrry this is such a novice question especially since I use to sell 300k a month of comp hardware for 5 years in the early 2000's!! Thanks in advance for the any assistance!