Haswell (microarchitecture)

Haswell is the codename for a processor microarchitecture developed by Intel. It is the successor to the Ivy Bridge microarchitecture and was launched in 2013. Haswell introduced several significant improvements over its predecessor, focusing on performance per watt and expanding into new mobile computing form factors.

One of the key features of Haswell is its increased integration. The voltage regulator, previously located on the motherboard, was moved onto the processor package. This allowed for finer-grained power control and reduced motherboard complexity, improving overall energy efficiency, especially important for laptops and other mobile devices.

Haswell also introduced new instruction set extensions, including Advanced Vector Extensions 2 (AVX2), which expands the vector processing capabilities of the processor. AVX2 allows for 256-bit integer instructions, further enhancing performance in computationally intensive tasks such as video encoding and scientific simulations.

The microarchitecture utilizes a tick-tock development model, representing a "tock," which means a new microarchitecture rather than a simple process shrink of the previous architecture. Haswell features improved branch prediction, larger caches, and a wider execution unit, all contributing to increased performance.

Haswell processors were available in several different variants, targeting different market segments. Desktop processors were typically designated as "K" series (unlocked for overclocking), "S" series (lower power), and standard versions. Mobile versions included "U" series (ultra-low power), "Y" series (extremely low power), and "H" series (high-performance mobile). These variants allowed Intel to address a wide range of devices, from high-end gaming desktops to ultraportable laptops and tablets.

The successor to Haswell is the Broadwell microarchitecture, which represents the "tick" in the Intel's tick-tock model, shrinking the process while maintaining the core architecture.