Core stepping

Over course of its life, each microprocessor core could be refined or tweaked multiple times without changing or adding any major processor features. The purpose of the tweaks is to eliminate existing errata (errors in microprocessor logic), improve processor's stability or reliability, and/or enhance some electrical, thermal or other processor characteristics. Each new core revision with these changes are referred to as a core stepping, and the changes never affect CPU performance. In this aspect the core steppings are different from new core generations, which always affect CPU performance. In modern x86 microprocessors core steppings are represented as one or more letters followed by a digit, for example B0, D1, etc. Core steppings are usually reset when a new core or new micro-architecture is introduced. Depending on the manufacturer, a processor with specific part number may be produced with one stepping (AMD K8 and K10-based CPUs), or multiple core steppings (AMD K7 and older, and Intel CPUs).

Knowing processor's exact stepping could be beneficial when you:

• need to match the processors for use in multi-processing system,
• get CPU that fixes certain errata,
• determine stepping-specific electrical and thermal characteristics, or
• to estimate your chances of successful processor overclocking.