CPU Affinity is a technique that allows processes on a multi-core processor to be targeted to specific CPU cores. The idea behind it is to improve the performance and stability of the system by making optimal use of the processor's resources. Assigning CPU affinities allows processes to run on specific cores, providing greater performance and stability because processes don't interfere or interfere with each other. This technique is often used in high-performance applications such as web servers, database servers, and other compute-intensive applications.