Over the past years, Intel supremacy in the server market has been challenged by AMD and more recently by NVidia with its GPGPU solutions that offer such raw power for massively parallel computing. In order to strengthen its offer, Intel released a new server board, aka Jefferson Pass:

The card is 16x45 cm, and despite such small size factor, it offers about the same components, connectics and expandability than a Xserve: 8 Xeon E5, 8 memory slots, PCI-Express 3.0 16x, etc. It only lacks SAS or SATA, but this can be added via a daughter card.
Such cards will be available to be racked in high density in computing cupboard in order to offer a high density of CPU and a huge processing power. With such design it would be possible to design smaller Mac Pro than the current enclosure we know. We actually start to worry that the delay in releasing the new Mac Pro by Apple would indicate that the Mac Pro might end soon to the same RIP list of Pro-dedicated hardware models... following the Xserve.
