BAD HARDWARE WEEK

Picture shows why: Intel bus based Xeon servers are bandwidth starving in 32 and 64 core configurations.
So, Intel needs Itanium for 32 and 64 core configurations. Until Nehalem arrive in 2009.



We all know that Microsoft Longhorn is currently troubled to pool off Intel's miserable ccNUMA performance.

The results also show that the poor local-memory bandwidth in commodity Intel-based systems, rather than the latency of remote-memory access, is often the main contributor to poor scalability and performance.

And local memory bandwidth depends on ... many things Xeon lacks. Integrated memory controller, hardware support for ccNUMA that extremely accelerates comuting , etc.
XEON is simply a synonym for bad multicore performance, that is why we still have ill fated Itanium as Intel's king of the performance hill.
It is quite natural that Intel is in panic after forthcoming Barcelona introduction. We could expect in a week or so NDA termination. Than the benchmarks will immediately show sorrow truth.
Xeon is a sucker.
Actually, the ccNYMA winning key is in the elusive solution that allows dynamic, adaptive performance optimizations. Intel will lack it in the next 3 years. Quite enough for you to drive out one Barcelona based server until then. If you are interested only in Intel shares, then think twice.
P.S. For those who wants to know more on Evaluating the Memory Performance of a ccNUMA System, please download enlightening PDF here. This picture below is on what Xeon is essentially lacking, but not quad core Barcelona (MCM glueing two dies or 45nm implementation will not help Intel without Nehalem new core in 2009):

We know that Cray favorize AMD over Intel's X86-64. This picture reveals why. Barcelona has Craylink compatible interface inside its die.
On the other side, AMD has its own problem with memory standards adoption. That will fix AMD's significant performance advancements to the moments when some new needed socket type is intoduced for the new DRAM interface applied. Say DDR3 in 2009. Until then Intel will heat and sweat running after competition.