This should be an easy question...I'm looking to get some DDR3 RAM for my computer and I think I want to go with G.Skill. My question is, would getting two 4GB packs of RAM be the equivalent of getting one 8GB pack? If so, why are two 4GB (2x2GB) packs usually cheaper than one 8GB (4x2GB) pack?
The reason, of course, is that we're talking dual channel vs. quad channel. What's the difference? Absolutely nothing. This is just a marketing thing.
Generally, two DC kits can work together to achieve QC architecture.
Be wary though, some of the manufacturer's tech support will not RMA your RAM if you buy a kit (or two) for other than its labeled purpose. I've seen a lot of threads here where two kits wouldn't play nicely together and the consumer(s) couldn't get anything from the manufacturer.
The savings of the two 4GB kits vs the one 8GB kit is what, 20 bucks? If you're that frugal, I'd e-mail the manufacturer tech support, before purchasing, to get their "official" answer of whether or not using the two kits together will produce the results you desire.
Along those same lines I'd get the 2 4gb packs --- If there is a problem with 1 module you only neeed to RMA the one kit and can still use the other kit while awaiting the RMA - If you buy the 8GB. kit the entire kit must be RMA'd and you can not use the system during that time !!
The only real benefit of the 8gb. kit is you know they are from the same manufacturing line and have been tested to run together - where the 2 4 gb. kits may be from different assembly lines\dates and there is the possibility of a difference in the actual chips - but they should be fine to work together.