Field Guide · hardware

Also known as: PC case, Chassis, Tower

A computer case is the enclosure that houses and protects a desktop computer’s components, giving each part a place to mount and a path for air and cables.1

CPU motherboard PSU drive bay graphics card intake exhaust airflow →
The case gives every part a home and a path for air: the motherboard and CPU on one wall, the power supply in a bottom bay, drives up front, and a graphics card in a slot — with a front intake and rear exhaust fan pulling cool air across the hot parts.

Overview

The case holds the motherboard, the power supply unit, drives, and expansion cards, with standoffs and brackets sized to standard layouts. Its job beyond mounting is thermal: fans and vents move air across the hot parts so cooling keeps the CPU and GPU from throttling. Good cases also route cables out of the airflow, which keeps the machine both tidy and cool.

Cases come in a range of sizes, and each is built to accept a particular motherboard form factor such as ATX or Mini-ITX. Bigger cases take bigger boards, more drives, and larger coolers; smaller ones save desk space but tighten every clearance.

Sizes

Case size is chosen to match the board and the amount of expansion you need:

Case size Board it fits Drive / card room Best for
Full tower E-ATX, ATX Most Workstations, big cooling
Mid tower ATX, Micro-ATX Plenty Typical desktop / gaming
Mini tower Micro-ATX Some Compact desktop
Small form factor Mini-ITX Minimal Living room, small desk

Where it fits

The case is the one part that does no computing yet shapes the whole build: it decides which boards fit, how many drives and cards you can add, how quiet the machine runs, and how it looks on the desk. A roomy tower eases upgrades and airflow; a small case saves space at the cost of expansion and cooling headroom. A pre-built all-in-one computer or mini PC hides this choice inside a fixed enclosure — fine for a GopherTrunk host that never needs opening, less so for a bench you plan to grow.

Sources

  1. Computer case — Wikipedia, on PC cases and their role. 

See also