Hardware acceleration

In computing, hardware acceleration is the use of computer hardware to perform some functions more efficiently than is possible in software running on a more general-purpose CPU. Examples of hardware acceleration include blitting acceleration functionality in graphics processing units (GPUs) and regular expression hardware acceleration for spam control in the server industry.

Traditionally, processors were sequential (instructions are executed one by one), and are designed to run general purpose algorithms controlled by instruction fetch (for example moving temporary results to and from a register file). Hardware accelerators improve the execution of a specific algorithm by allowing greater concurrency, having specific data-paths for its temporary values, and possibly reducing the overhead of instruction control. Modern processors are multi-core and often feature parallel SIMD units; however hardware acceleration still yields benefits.

Hardware acceleration is suitable for any repetitive, intensive key algorithm. Depending upon granularity, hardware acceleration can vary from a small functional unit, to a large functional block (like motion estimation in MPEG-2).

The hardware that performs the acceleration, when in a separate unit from the CPU, is referred to as a hardware accelerator, or often more specifically as a 3D accelerator, cryptographic accelerator, etc. Those terms, however, are older and have been replaced with less descriptive terms like video card or network adapter.

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