Nehalem (microarchitecture)


Nehalem is the codename for an Intel processor microarchitecture released in November 2008. Nehalem was used in the first generation of the Intel Core processors. Nehalem is the successor to the older Core microarchitecture.
The Intel codename "Nehalem" was taken from the Nehalem River. It is an architecture that differs radically from Netburst, while retaining some of the latter's minor features. Nehalem-based microprocessors use the 45 nm process, run at higher clock speeds, and are more energy-efficient than Penryn microprocessors. Hyper-threading is reintroduced, along with a reduction in L2 cache size, as well as an enlarged L3 cache that is shared among all cores.
Nehalem was replaced with the Sandy Bridge microarchitecture, released in January 2011.

Technology

It has been reported that Nehalem has a focus on performance, thus the increased core size.
Compared to Penryn, Nehalem has:
Overclocking is possible with Bloomfield processors and the X58 chipset. Lynnfield processors use a PCH removing the need for a northbridge.
Nehalem processors incorporate SSE 4.2 SIMD instructions, adding seven new instructions to the SSE 4.1 set in the Core 2 series. The Nehalem architecture reduces atomic operation latency by 50% in an attempt to eliminate overhead on atomic operations such as the LOCK CMPXCHG compare-and-swap instruction.

Variants

Roadmap

The successor to Nehalem and Westmere is Sandy Bridge.