I wish to buy 8gb of ram but feel in the near future I might need/want more, this is a digital audio workstation for uni. I can buy 1x8gb and sacrifice dual channel untill I upgrade or buy 2x4gb and sacrifice a max ram of 16gb and populate all four slots. I won't be over clocking at all (xeon e3 1230v3) and I don't think I will ever use 32gb ram; although you never know. I know someone will say go for it and get 16gb now but I really can't justify it right now, I would rather put the money elswhere in the build. Thanks for any replies.
If you feel like you will want 16gb or 32gb latter I wouldnt wait to long as it is only going to rise in price. The new ddr4 standard is supposed to be in the next 6mo to a year so prices will keep going up as produciton is shifted, there will be a price drop as ddr4 becomes the standard, and then the prices will climb agan as availibilty decreases.
The two modules in the pair work best if they match, but 1 pair does not have to match the other one. This is why motherboards have specific slots designated for ram pairs. ASUS uses A1 B1 A2 B2, so A1and A2 is one pair and B1 and B2 are a different pair, A pair and B pair can even be different brands (of course you want to match latency/timing/speed for best performance).
ANY time you mix DRAM, it can be and often is Problematic - even when you buy the same exact model...Mixing sticks from different packages isn't recommended. And contrary to the above comment, no the slots aren't made for 'different pair', on a dual channel mobo there is channel A and channel B each supports two slots, typical config is A1 and B1 or A2 and B2, one stick in each channel and the purpose is to enable dual channel. Each stick of DRAM by itself is a 64bit device, when dual channel is enabled then the 2 or 4 sticks that are populated are seen as 1 single 128bit device and run accordingly, they are aren't looked at and treated separately as in implied above. Further if you were to peruse the forums here and elsewhere, you will find the same thing over and over again, of people following the above "advise" and mixing sets of DRAM, only to find their rig won't boot, or gets BSODs galore, etc....simply because the sticks don't want to play together. It's always best to buy a single set of DRAM of the full amount you want/need, rather than face the possibility of RMAs, shipping fees, etc... Either go 2x8GB or if have doubts of needing that much a good 2x4GB set