Quoting from the Intel official announcement:
…
The six new Quad-Core Xeon® 7300 series processors can deliver more than twice the performance and more than three times the performance per watt over the company’s previous generation dual-core products.
…
In addition to twice the cores, the 7300 series and Intel 7300 chipset offer up to four times the memory capacity of Intel’s previous MP platforms, enabling very large consolidation ratios that can reduce space, power and operation costs.
…
With the introduction of the Xeon 7300, users will now be able to pool all of their Intel Core microarchitecture based server resources, whether they are single-, dual- or multi-processor based, into a dynamic virtual server infrastructure that allows live virtual machine migration that can improve usage models like failover, load balancing, disaster recovery, or server maintenance. The previously announced Intel VT FlexMigration will assist the seamless addition of Intel’s next generation 45nm Core microarchitecture-based platforms to such resource pools.
…
Pricing of these new quad-core processors depends on the speeds, features and amount ordered, and ranges from $856 to $2,301 in quantities of 1,000…
Virtual Iron is the first company to announce support this new processor in just released Virtual Iron 4.0 platform.
AMD announced a similar technology under the name of AMD-V Extended Migration.