Dual Channel RAM Question

Hey guys,

I'm looking to buy a 512MB stick of DDR2 RAM Right now...then later drop in another 512.

I parted out my other 256MB stick into my second Rig so I could run it...as I don't have another stick of RAM and I need that computer up to run my TV Tuner.

So my question is...do the sticks of RAM HAVE to be a pair when bought...or if I just buy the same model again, will it run dual channel?

Thanks, ps2cho

As long as the timings are matched it shouldn't be a problem but getting the same brand/model would be best.