Nehalem /nəˈheɪləm/[1] is the codename for Intel's 45 nm microarchitecture released in November 2008.[4][5] Nehalem is built on the 45 nm process, is able to run at higher clock speeds without sacrificing efficiency, and is more energy-efficient than Penryn microprocessors.Nehalem is an architecture that differs radically from NetBurst, while retaining some of the latter's minor features.Nehalem later received a die-shrink to 32 nm with Westmere, and was fully succeeded by "second-generation" Sandy Bridge in January 2011.It has been reported that Nehalem has a focus on performance, thus the increased core size.