Nehalem is the codename for an Intel processor microarchitecture, successor to the Core microarchitecture. Nehalem processors use the 45 nm process. A preview system with two Nehalem processors was shown at Intel Developer Forum in 2007. The first processor released with the Nehalem architecture was the desktop Core i7, which was released in November 2008.
Nehalem, a recycled codename, refers to a completely different architecture from Netburst, although Nehalem still has some things in common with NetBurst. Nehalem-based microprocessors utilize higher clock speeds and are more energy-efficient than Penryn microprocessors. Hyper-Threading is reintroduced along with an L3 Cache missing from most Core-based microprocessors.