"Extreme goes quad-core too
Intel also announced that, in addition to a dual-core version launched in July, the Intel® Core2 Extreme processor brand will now include a quad-core version to be launched later this year. Buyers will be able to identify each version through both the full product name and unique processor number.
Both of these new processors will feature industry-leading Intel® quad-core technology and will extend the performance and technology leadership of the Intel® Core2 processor brand"
try this link http://www.intel.com/apac/core2duo/future.htm