Dual-Channel question [ignorance]

I generally overclock CPUs and know virtually nothing about RAM; I'm getting an a7n8x Deluxe with either a half gig or full gig of dual-channel PC-3200.

How similar do the two RAM sticks have to be to run dual-channel? Identically coming in the same batch, meant for dual channel, or just of the same brand, or the same brand and same size, or same model but not necesarrily same batch, etc.?

Ideally, they only need to be identical in size. You are going to want to get two identical modules that, at the very least, share identical specifications and ICs. Buying two of the same modules, or even better, a Dual Channel kit, will save you unnecesary grief of having one module underperform the other.

Alright, thank you.

I want to get one 512 stick right away, and then the second 512 stick (the exact same model) about a month of two later. That should be fine?

And I guess 2 512s, one in each of the first 'channel' slots, and a third 512 in the second channel, won't work at dual?

That wouldn't work. The only way dual will work with 3 sticks is if slots 1 and 3 have 256 MB modules and slot 2 has a 512MB module, but that is hardly even worth it.

Why is it hardly worth it?

It has been known to cause instability and puts a load on the chipset. 2x 512 is much more ideal.