A reader wrote:
The Xeon chips are what go into the Mac Pro. While high clocking Ivy Bridge desktop chips could go into the new Mac Pro right now, Intel does not build desktop chips that work together in multichip machines. Only the Xeon chips do that. So a desktop-based Mac Pro can only use a single chip, a top of the line i7 with 4 cores.
A new Mac Pro can come out now with Sandy Bridge Xeons - they are shipping now and have been for some time - the Sandy Bridge chipsets do not support USB 3. Apple has refused to build USB 3 Macs until Intel supported it natively; there are several Steve Jobs remarks on this going back 2, 3 years now. Sure enough, the only Macs with USB 3 are those that use Ivy Bridge and its chipsets.
MPG: I checked on this, and the USB3 part is indeed correct, which means that if Apple is going to insist on USB 3, then it will be August 2013 or so for a new Mac Pro. Seems like a bad choice to me, but also very possible.