The Core
The Core i5-7xx series is a mainstream quad-core variant of the Core i7 and is based on the Nehalem microarchitecture. The Core i5-7xx series lacks Hyper-threading and use a slower 2.5 GT/s DMI bus like the Lynnfield-based Core i7 and the mobile Core i7 processors. The Core i5-6xx series are based on the Westmere microarchitecture and are dual-core. They have Hyper-threading and Turbo Boost along with an integrated graphics core. The Core i5-6xx series should outperform the Core i7 in tasks that utilize only one or two cores because of the radically high clock speed, which can be further increased using Turbo Boost.