To be used efficiently, all computer software needs certain hardware components or other software resources to be present on a computer system. These pre-requisites are known as (computer) system requirements and are often used as a guideline as opposed to an absolute rule. Most software defines two sets of system requirements: minimum and recommended. With increasing demand for higher processing power and resources in newer versions of software, system requirements tend to increase over time. Industry analysts suggest that this trend plays a bigger part in driving upgrades to existing computer systems than technological advancements.

Minimum system requirements

The 'Minimum system requirements' must be satisfied for the software to be usable at all. Computers with lower specifications than the minimum requirements may sometimes also run the software. It is suggested, however, that the user will not have a representative experience of the software this way. Generally this set is regarded more of a rule than a guideline. A system meeting this requirement will provide basic performance of a software application.

Recommended system requirements

Recommended system requirements are often suggested by software vendors for optimal performance of a software. Although not a necessity, this set of requirements is often sought after by power users who expect to gain a better experience of software usability. Recommended System Requirements do not promise best possible performance of a software and are treated as more of a guideline than a rule. Almost always a better system is available, or will be in future, to provide better performance. Also, exceeding by far these requirements does not guarantee to the user that everything will run with absolute smoothness and look its best. More often than not, games are a bit disappointing in this respect, presenting issues that may or may not be corrected with future modifications.

Hardware requirements

The most common set of requirements defined by any operating system or software application is the physical computer resources, also known as hardware, A hardware requirements list is often accompanied by a hardware compatibility list (HCL), especially in case of operating systems. An HCL lists tested, compatible, and sometimes incompatible hardware devices for a particular operating system or application. The following sub-sections discuss the various aspects of hardware requirements.

Architecture

All computer operating systems are designed for a particular computer architecture. Most software applications are limited to particular operating systems running on particular architectures. Although architecture-independent operating systems and applications exist, most need to be recompiled to run on a new architecture. See also a list of common operating systems and their supporting architectures.