Ultralight computers often use ULV (ultra low voltage) processors that are cooler but slower and more expensive than mainstream chips. Apple has compromised by getting Intel to produce an Intel Core 2 Duo in a smaller package "that was originally reserved for mobile Penryn due out in the second half of 2008 with the Montevina SFF Centrino platform. Intel accelerated the introduction of the packaging technology specifically for Apple it seems," reckons AnandTech.
Basically, the MacBook Air is running an Intel Core 2 Duo (normally generating 35W) at 20W, rather than using an off-the-shelf LV (17W) or ULV (10W) design.
Anandtech says:
The bigger concern however has nothing to do with packaging technology or operating voltages, but overall thermals. The MacBook Pro runs very hot and while the 20W TDP of the MacBook Air is significantly lower than the 35W TDP of the Pro, it's high for such a small chassis. We won't know for sure how hot the Air will get until it's in our hands but the SSD [solid state drive] route seems like an even better bet now that we know a little more about what we're dealing with. Cutting down heat in that thin chassis will be very important, and moving to solid state storage is the only real option you have there.
Of course, the MacBook Air also has a smaller and slower hard drive than similar ultraportables, which will also reduce both heat and cost, allowing for a more competitive price.
Charles Arthur adds: George Ou at ZDNet says that the chip is a 65-nanometre product, not the 45nm "Penryn" chip that was announced earlier this month. The die is the Penryn size, though. Why? Probably because given the long lead times that would be needed for this product, Intel wasn't able to provide enough working samples at 45nm. To be certain of having something it could sell, Apple needed to go with the 65nm product. Shrunk like that, it'll have to run slower, else thermal problems in the chip would make it very unstable.
But that also implies that the MBAir will be updated with the new working 45nm Penryn chips in the future. But probably not by the time it goes on sale in February...
Jack adds: Actually, Charles, the die isn't Penryn size. The packaging is mobile Pennryn size. It's a kludge. ;-)
If you see the quote above, the mobile Penryn package was "due out in the second half of 2008 with the Montevina SFF Centrino platform." If that's still true, Apple won't find it easy to slot in current 45nm Penryn chips. I expect these are (for PC compatibility) shipping in the larger Merom packaging.
