Those are also dual core machines. You don't have just a "dual core" machine. You have an Intel Core Duo or Core 2 Duo. That's because they were early members of the "Intel Core" family of processors, but are the new additions in that line up are the core i3, i5, i7, and i9s. The core i3 is strictly a dual core chip. i5 is most often times (and in the case of the MacBook pros) also a dual core chip, though in the iMacs it is a quad core chip clocked at 2.66GHz. While the dual core i5s support hyper threading (i.e. running 2 processes per core), the quad core i5 does not. Both however support the intel turbo boost technology. The i7 is most often times a quad core chip (in mobile and desktop classes). However, as in the case of the MacBook pros and some other custom build computers, the i7 can also be a dual core chip with a higher clock speed than its mobile quad core companion (2.66GHz dual vs 1.6GHz quad). The dual core i7 will also turbo boost BOTH cores up to 3.06GHz, and a single core up to 3.33GHz, whereas the quad core mobile companion will have a max turbo boost on 1 core up to 2.8GHz. The i9 is (as far as I know) only a hexacore CPU, and has yet to be released.