Hi, Looking at Wikipedia's page on Nehalem, I noticed that only one of the processors supports FB-DIMMs - that is, the 8-core model (Beckton). If there are 8 cores in one package, Apple only has a few options for the base model: 1. Keep Harpertown. Increase the clock speed. Keep Nehalem for BTO configurations. Pros: Keeps the base-model cost down Cons: Nehalem has a radically different architecture (QuickPath and an Integrated Memory Controller). You can't just plug in a Harpertown. These would be two entirely different systems. 2. Have Intel make a custom Gainestown with FB-DIMM support, and use two of them. Pros: Both have an IMC and QP, so system architecture would be similar if not identical Cons: A custom processor would likely be expensive, and Intel might not be able to deliver 3. Use two Beckton processors, to make the base model 16-core. Pros: Clock speeds can be increased on BTO. Obvious upgrade path. Don't need to rely on custom parts from Intel, at a time when their production is going to be at capacity Increased power in the base model gives good value for buyers Cons: Could be prohibitively expensive 4. Use a single Beckon processor in the base model, offer upgrade to dual Becktons (16-core) Pros: Increases the power, without substantially increasing cost Cons: FSB (QP) could be a performance bottleneck Traditional upgrade is through higher CPU clocks - this would complicate the upgrade path Buyers would be tempted to upgrade the CPU themselves, which is not a user-serviceable part In response to point 2, Apple could use DDR3 for the base mac pro (Wikipedia states modules with up to 16GB capacity, keeping the capacity benefit). I don't think they'll do this, as it would complicate the product range too much. Apple tends to like small upgrades across one product - they wouldn't like to change the CPU and the type of memory used by the machine. I think option 4 is the most attractive from Apple's perspective. Yes, it would complicate the upgrade scenario somewhat, and bottlenecks may prevent the performance enhancements many are expecting, but it's the smartest business option to go for. Of course, if they can afford to cut their margins a little, option 3 would be most favourable to buyers. I know we say this with every revision, but the amount of internal redesign that Nehalem brings could tempt Apple to perform some external design changes.