What's faster: 2.7GHz dual-core or 2.2GHz quad-core?

Assuming that both are of the same generation, i.e. Intel Core I7 (Gen 2), the dual core would actually be faster because many programs cannot work with multi-threads. BUT, if you bought the quad core, you could easily overclock the CPU in the bios to 2.7 GHz and they would be equally as fast, but the quad core could handle many more open programs simultaneously.