Signs of a long-in-waiting Mac Pro update have appeared in earnest through the Apple Store. Picking either the 12-core stock workstation or most build-to-order changes knocks the shipping time back to between one to three weeks, usually a sign at Apple that supplies are dwindling. A refresh isn't necessarily imminent and might depend on both the sales rate of remaining stock and how soon new components are ready.
Apple hasn't updated the Mac Pro since July 2010. The update has primarily been waiting on Intel, which hasn't had a mid-range Xeon update since. Its Xeon E5 update will be that replacement and was pushed back to early 2012, missing virtually an entire generation while the entry E3 and server-focused E7 shipped. The E5 moves to the much newer Sandy Bridge architecture's 32 nanometer design, new media instructions, and other upgrades to make it more efficient per clock.
Apple has already dropped hints as to other elements of the presumed Mac Pro upgrade, such as references to Radeon HD 7000 cards in the Mac OS X 10.7.3 beta. Its allusion to the Tahiti core hints at either the high-end Radeon HD 7970 or a new sub-variant, such as a possible 7950, being at least a build-to-order option.
Concerns have existed that Apple might drop the Mac Pro entirely, which could see a simple winding down of the line. When Apple discontinued the Xserve, though, it gave possible buyers significant advance notice so they could plan purchases and complete projects before it was too late. As the only Mac that could be considered a heavy-duty server as well as the emblem of its creative software, though, its disappearance is less certain, especially in the light of the pro-oriented Thunderbolt port and imminent new Xeons. [viaMacRumors]