Computer hardware: Difference between revisions

Revision as of 13:50, 18 August 2025

Revision as of 09:55, 19 August 2025

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Components directly attached to or to part of the motherboard include:

* At least one [[central processing unit|CPU]] (central processing unit), which performs the majority of computational tasks required for a computer to operate.{{sfn|Wang|2021|p=8}} Often described informally as the "brain" of the computer,{{sfn|Wang|2021|p=9}} the CPU fetches program instructions from [[random-access memory]] (RAM), decodes and executes them, then returns results for further processing by other components. This process is known as the [[instruction cycle]]. Modern CPUs are [[microprocessor]]s fabricated on a [[metal–oxide–semiconductor]] (MOS) [[integrated circuit]] (IC) using advanced [[semiconductor device fabrication]] techniques, often employing [[photolithography]]. They are typically cooled using a [[heatsink]] and [[computer fan|fan]] or a [[liquid cooling|liquid-cooling system]]. Many contemporary CPUs integrate an on-die [[graphics processing unit]] ([[integrated graphics|GPU]]), eliminating the need for a discrete GPU in basic systems. CPU performance is influenced by clock speed—measured in gigahertz (GHz)—with common consumer processors ranging from 1 GHz to 5 GHz.{{cn|date=August 2024}} Additionally, there is a growing trend toward [[multi-core processor|multi-core designs]], where multiple processing cores are included on a single chip, enabling greater [[parallel computing|parallelism]] and improved multitasking performance.{{sfn|Wang|2021|p=9}}

*The internal bus connects the CPU to the main memory withvia severalmultiple linescommunication for simultaneous communication—typicallylines—typically 50 to 100—which are separated100—divided into thoseaddress, fordata, addressingand orcontrol memorybuses, data,each andhandling commandspecific ortypes controlof signals.{{sfn|Wang|2021|p=75}} AlthoughHistorically, parallel buses usedwere todominant, bebut morein commonthe twenty-first century, high-speed serial buses with(often ausing [[serializer/deserializer]] to(SerDes) sendtechnology) morehave informationlargely overreplaced thethem, sameenabling wiregreater havedata becomethroughput moreover commonfewer inphysical theconnections. twenty-firstExamples centuryinclude [[PCI Express]] and [[USB]].{{sfn|Wang|2021|p=78}} ComputersIn systems with multiple processors will need, an interconnectioninterconnect bus is used, usuallytraditionally managedcoordinated by a [[Northbridge (computing)|northbridge]] chip, whilewhich links the CPU, memory, and high-speed peripherals such as [[PCI]]. The [[Southbridge (computing)|southbridge]] manageshandles communication with slower peripheral and I/O devices such as storage and USB ports.{{sfn|Wang|2021|p=90}} However, in modern architectures like [[Intel QuickPath Interconnect]] or [[AMD Ryzen]]-based systems, these functions are increasingly integrated into the CPU itself, forming a [[system on a chip]] (SoC)-like design.

*[[Random-access memory]] (RAM), which stores the code and data that are being actively accessed by the CPU in a hierarchy based on when it is expected to be next used. [[Processor register|Register]]s are closest to the CPU but have very limited capacity.{{sfn|Wang|2021|p=47}} CPUs also typically have multiple areas of [[cache memory]] that have much more capacity than registers, but much less than main memory; they are slower to access than registers, but much faster than main memory.{{sfn|Wang|2021|pp=49-50}} Caching works by prefetching data before the CPU needs it, reducing latency.{{sfn|Wang|2021|pp=49-50}}{{sfn|Hennessy |Patterson|2011|p=45}} If the data the CPU needs is not in the cache, it can be accessed from main memory.{{sfn|Wang|2021|pp=49-50}} [[Cache memory]] is typically [[Static random-access memory|SRAM]], while the main memory is typically [[DRAM]].{{sfn|Wang|2021|p=3}} RAM is volatile, meaning its contents will disappear if the computer powers down.{{sfn|Wang|2021|p=54}}

*Permanent storage or non-volatile memory is typically higher capacity and cheaper than memory, but takes much longer to access. Historically, such storage was typically provided in the form of a hard drive, but [[solid-state drives]] (SSD) are becoming cheaper and are much faster, thus leading to their increasing adoption. USB drives and network or cloud storage are also options.{{sfn|Wang|2021|pp=55–56}}