Computer tower

Compared to a pizza box case, the tower tends to be larger and offers more potential for internal volume for the same desk area occupied, and therefore allows more hardware installation and theoretically better airflow for cooling.

[1] Computer systems housed in the horizontal "pizza box" form factor—once popularized by the IBM PC in the 1980s but fallen out of mass use since the late 1990s—have been given the term desktops to contrast them with the often underdesk-situated towers.

[6][5]: 138  Some full-tower cases included locking side-doors and other physical security features to prevent theft of the discs inside those bays.

Full-tower cases may also have increased dimensional depth and length over their shorter counterparts, allowing them to accommodate Extended ATX motherboards, larger graphics cards and heat sinks.

Mini-towers typically will only accommodate microATX motherboards and for this reason sell in fewer numbers in the consumer market than the other size classes of computer towers.

[4][22]: 20 [23]: 57 The tower form factor may be seen as a proportional miniaturization of mainframe computers and minicomputers, some of which comprise massive tall enclosures standing almost to the ceiling.

[25] In 1982, NCR introduced the Tower series of workstation computers, named so for their tall, upright configuration, intended to be stowed away under a desk.

[35] According to The New York Times in 1988, the PS/2 Models 60 and 80 started the trend of computer manufacturers offering IBM PC compatibles in optional tower form factors: A countertrend is to take PCs off the desk and put them on the floor.

[37] Recommending such kits in The Washington Post in 1989, Brit Hume called the tower the best configuration for ergonomics and noted that, "Contrary to popular myth, standing vertically will not hurt the computer or throw off your disk drives.

[38] Computer cases or pre-built systems offered in the traditional horizontal form factor have since been separately categorized as desktops, to contrast them with the usually-floor-situated towers.

[21] Brian Benchoff of Hackaday argued that the popularity of the Macintosh Quadra 700 was the turning point for computer manufacturers to move over to the tower form factor en masse.

A mid-tower computer case from c. 2011
A full-tower computer case from c. 2010
An SGI Onyx deskside computer
The horizontally configured system unit of the original IBM PC set a de facto standard for the physical setup of personal computers from the early 1980s to the mid-1990s.
An IBM PS/2 Model 60 (left) and an PS/2 Model 80 (right) side by side. These models were IBM's first Intel-based PCs built in a tower form factor.