ARCHIVED: What does form factor mean?

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Form factor is used to describe the physical size and shape of a computer device measured by outside dimensions. It is most often used to describe the size of circuit boards, especially the motherboard and expansion cards. When used to describe hard drives, the form factor is the diameter of the platters and case, such as 3.5" or 5.25", not the drive's storage space.

Motherboards come in various sizes and shapes. Common form factors for PC motherboards include the AT and baby AT form factors, and the ATX, LPX, and NLX form factors.

For additional information on form factors and related case design issues, please see:

  http://www.pcguide.com/ref/mbsys/mobo/form.htm

  http://www.pcguide.com/ref/case/