The group includes the single-core `` Core 2 Solo '' , dual-core ( 2 cores ) `` Core 2 Duo '' , and quad-core ( 4 cores ) `` Core 2 Quad '' microprocessors . The Core 2 brand was introduced on July 27 , 2006 , comprising the Solo ( single-core ) , Duo ( dual-core ) , Quad ( quad-core ) , and in 2007 , the Extreme ( dual - or quad-core CPUs for enthusiasts ) subbrands . Intel Core 2 processors with vPro technology ( designed for businesses ) include the dual-core and quad-core branches .