We have two new components in play here. First are AMD's new triple- and quad-core Phenom II processors. Second is Asus' Socket AM3-based M4A79T.
If you take Socket AM3 out of the picture, the new Phenom IIs mainly serve to fill in and update AMD's processor lineup with its 45 nm technology. Because they drop right into AM2/AM2+ motherboards, you could almost ignore the fact that they sport 938 pins and just be happy AMD is augmenting the mid-range and entry-level nooks in the Phenom family with chips loaded with more cache, higher clocks, and significantly improved scalability.
But there's also the AM3 interface itself to consider. AMD doesn't necessarily think the Phenom II + DDR3 story is fully baked yet. Even though we saw respectable throughput gains in shifting from DDR2 to DDR3, those increases don't necessarily translate into real-world performance improvements. Nevertheless, our benchmark results certainly weren't damning of DDR3. In fact, in most cases, the Phenom II X4 810--the 2.6 GHz processor with a stripped-down 4 MB L3 cache--was able to outperform our simulated Phenom II X4 910 with its full 6 MB cache. Moreover, we saw plenty of evidence in our system power tests to indicate that Phenom II and DDR3 together yield one of the most efficient performance platforms we've had the chance to test.
With that said, adopting AM3 does require one of the Phenom IIs being introduced today. It'll also necessitate a motherboard like the Asus M4A79T Deluxe with an AM3 interface. And you'll need DDR3 memory, which remains significantly more expensive than DDR2. Given no real tangible performance gains and really only the energy savings of which to speak, stepping up to a fully AM3-compatible platform, not surprisingly, doesn't make sense today.
What does make sense is the Phenom II X3 720 Black Edition on an existing AM2/AM2+ setup, leveraging cheap DDR2 memory. Gone are the days of Core 2 Duo's dominance over the value-oriented gaming market. Now that AMD has its hat in the ring, there's a lot more to like about the oddness of three cores.