Intel has issued a new product change notification (PDF), or PCN, to partners in regards to dual and quad-core Xeon stepping changes. The stepping change brings the dual and quad-core Intel Xeon 5100 Woodcrest and 5300 Clovertown processors to stepping G0. G0 introduces energy efficiency and virtualization enhancements.
Stepping G0 reduces power consumption during C1E halt states. Intel does not state how much less power stepping G0 processors consume in idle states except “some amount.