SpeedStep

SpeedStep, short for Intel SpeedStep Technology, is a processor power-management feature developed by Intel to improve energy efficiency by dynamically adjusting the CPU’s voltage and frequency in response to current workload. By scaling voltage and clock speed up or down, SpeedStep aims to maintain usable performance while reducing power consumption and heat, which is especially beneficial for mobile devices.

The technology relies on dynamic voltage and frequency scaling (DVFS) and operates through a set of processor power states, commonly referred to as P-states. When the system is idle or lightly loaded, the processor can drop to lower frequency and voltage, lowering power draw. When demand increases, the processor can raise frequency and voltage to restore performance. Enhanced versions of the feature, often called Enhanced Intel SpeedStep Technology (EIST), provide tighter OS integration and a broader range of P-states for finer-grained control.

Historically, SpeedStep was introduced to address the power and thermal constraints of mobile computing and later became standard across many Intel CPUs, including desktop and laptop variants. It is typically enabled by the system firmware and coordinated with the operating system through ACPI power-management interfaces. Modern CPUs and OSes continue to use SpeedStep or its evolved forms to optimize performance-per-watt, with users generally experiencing smoother transitions and longer battery life without explicit configuration.

Notes: SpeedStep requires support from the CPU, motherboard firmware (BIOS/UEFI), and the operating system. When enabled, it is usually transparent to users, though some laptops offer BIOS or OS settings to customize or disable DVFS behavior.