Step 3: Navigating Between DDR and DDR-2

Here's a little secret, on the whole DDR-2 RAM has been a bit of bust. Touted as the memory of the future, able to leap small buildings in a single bound for everything from videocards to motherboards.
It promised a lot and delivered little in the real world. Yet since the entire computer industry is shifting towards DDR-2 RAM, we're all resigned to the fact that it's here to stay until FB-DIMM and DDR-3 RAM break out in 2007/2008.
Of course DDR-2 memory isn't all bad, it offers a greater level of bandwidth between memory and processor, and that's a good thing. It's just that single-core Intel systems (the current largest segment consuming DDR-2 RAM) aren't very inspiring, and the wonderfully low timings associated with DDR memory have been cast aside for a pointless frequency game. There's a difference between PC2-6400 with high lanencies, and PC2-6400 with low latencies when it comes the benchmarks, and so far the latter has been sadly overlooked for far too long.
By the end of May, AMD's Socket AM2 Athlon64 processor will be running along on DDR-2. The socket AM2 Athlon64 isn't expected to demand a ton of bandwidth from the get-go, but rather benefit more from DDR-2 memory with tighter CAS latency timings. Unfortunately at the moment these types of parts are missing from the DDR2 memory equation so it's hard to offer commentary on where this will all be headed.
It's very likely that initial Socket AM2 Athlon64's will perform no better, or no worse than equivalently paced Socket 939 counterparts. Between now and then, perhaps AMD will have tweaked the memory controller to utilize more memory bandwidth, or DDR-2 memory latencies will have dropped somewhat. Like you, I'm still waiting to see.
The saga isn't yet written, and pre-release glimpses of Socket AM2 performance by way of Engineering Sample CPUs are only telling half the story. It will be interesting to see what happens, but certainly the prevalence of DDR-2 RAM is unrelenting.