blackfalcon makes a good point: get low cas 2.5 or 2 if you can afford it, but if you get 3 and don't plan on o/c'ing, don't sweat it. You want to install your ram sticks in two's, slot 1/3, 2/4 to enable the dual channel mode, which is what you are after. if you increas your ram above 2, don't just add 1 -- that will cost performance by turning off the dual ddr mode. Add 2, you will keep your dual mode. Again, running at normal clock speeds the performance penalty of cas 3 is very small, I think I stuck 2.5 in mine, works just fine.