So there’s a massive amount of “discussion” about what’s going on and what it means. Unfortunately, most of the people involved with these discussions are totally clueless. Here’s what’s actually going on.
Apple chose to use the Core Duo in their iMac because it’s a better chip than the P4 and “Core 2″ wasn’t around. Also, it means the iMac can share its internal design with the MacBook and MacBook Pro. Maintaining 2 designs (MacBook [Pro]/[i]Mac [Mini] and Mac Pro) is easier than maintaining 3 designs so as long as the chips perform well compared to their “desktop” counterparts and supply isn’t an issue, it makes sense for Apple to do this.
Intel has 3 “Core 2″ products: Merom (mobile), Conroe (desktop) and Woodcrest (Xeon). Reports are that Intel’s manufacturing is running at 70% Woodcrest, 20% Conroe and only a trickle of Meroms. I’m not so convinced of the numbers (I don’t think they come from Intel) but I certainly wouldn’t be surprised if there are more Conroes being made than Meroms. The PC industry seems to be picking up Conroe for desktop machines but is still using Pentium M or Core Duo chips for many laptops.
The Merom is a drop-in upgrade for Core Duo but there are limitations with this. Most importantly, the chipset remains 32-bit so you can’t have more than 4 GB of address space (only 3 GB RAM, since around 1 GB is needed for device I/O space). Most important for Apple though is that dropping in a Merom brings the iMac to about the same performance as PCs with Conroe have. Apple could redesign the iMac to use Conroe but that would take longer and mean maintaining 3 designs instead of 2.
Despite a claimed 20% increase in performance from Core Duo to Merom, people aren’t seeing this on actual PC laptop that are shipping. This makes it less important to have a Merom in a laptop. In fact, other than different model number, there’s nothing to differentiate a Core Duo and a Merom in marketing material. The platform name for both chips is Centrino Duo. The thing that will really help the Merom pull away from Core Duo is the new 64-bit capable chipset but as with Conroe, that means a new design. Delaying the Merom in laptops gives Apple a chance to build a system based on the new chipset so that there’s a significant performance improvement.
So Apple’s use of Core Duo for most of it’s machines is the primary cause of the current situation. Other than the current supply shortages, doing this is advantageous. Apple might consider switching the iMac over to Conroe but that’ll take time and money and might even ruin some of the nice points of the current systems (cool and quiet). The portables won’t see a significant advantage from a Merom upgrade right now so Apple’s using the limited chips they have to ensure the iMac remains competitive with desktop PCs. Going forward, I’d expect Apple to continue using Merom in the iMac. When they get a system design based on the new chipset, Meroms will go into the MacBook Pro. I think the Mini and MacBook will remain on Core Duo for a while yet. Core Duos are getting cheaper now and it’ll let Apple drop the price on these machines to pre-Intel levels while remaining relatively close to the performance of the other systems. Sure, it means having 3 designs around but the MacBook/Mini design has already been done so it’s not the same as aiming for a trio of Merom/Conroe/Woodcrest.
Finally, there’s been calls for a low end Conroe-based Mac Pro but unless the iMac switches to Conroe (which as I’ve said, is doubtful) that means a new system design for a single, low-end “pro” machine. Worse, it would be a system that directly competes with the iMac and while some people would like a non-all-in-one machine with similar specs to the iMac, I really doubt Apple will ever provide such a system. It’s just not something teh Steve is interested in.
