The latest discussions on dual core perhaps have missed the main point.
To get you started, google for "xen dual core".
The main point in newest CPU architectures - AMD and Intel - is likely the introduction of "Virtualization Technology".
This allows multiple operating systems to run on a common open source "Paravirtualization" host:
This development comes from Cambridge University but could not be implemented up till now without putting some constraints on the different operating systems. The new AMD and Intel "Virtualization Technology" removes this limitation and allows any OS to run unmodified.
As compared to VMWare virtualization, the Xen approach seems to offer quite a bit more flexibility, last but not least in I/O.
Some observers point out that the Virtualization Technology may in fact signify a paradigm shift in future computing also leading to ways to more efficiently take advantage of multicore architectures.
Yes.... However its also being driven by the application of maximum utilization efforts in datacenters.