New Xen features outlined for 3.3 release.
CPU Portability
Xen 3.3 now enables administrators to move active virtual machines from one server to another independent of various CPU virtualization support. This new feature offers greater flexibility in heterogeneous server farms with various CPU virtualization versions.
Green Computing
Xen 3.3 takes advantage of the latest hardware support for power consumption monitoring and reduction by intelligently powering down components within an individual processor. Power savings are also gained by offering virtualization solutions built on Xen the ability to manage servers and server farms for greater power savings.
Security
Xen 3.3 delivers new solutions to better secure virtual machine start-up as well reduce possible hacking opportunities by moving critical management processing out of global space into separate virtual sessions.
Performance & Scalability
Xen 3.3 significantly improves the already impressive Xen performance by offering new memory access algorithms to reduce system wait time during critical memory requests and new scanning technology to optimize framebuffer searches. Several scalability enhancements were also implemented including 2MB page support for EPT/NPT.
Also interesting is the updated list of the major Xen contributors: Intel, AMD, HP, Dell, IBM, Novell, Red Hat, Sun, Fujitsu, Samsung, and Oracle.
More details
http://blog.xen.org/wp-content/uploads/2008/08/xen_33-datasheet.pdf