Form Factors

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Form Factors
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Form Factor

• Describes the physical shape or outline of a
  motherboard and the location of the mounting
  holes
• Form factor also applies to the power supply and
  case
• Form factor must be considered when replacing or
  upgrading a PC to make sure the motherboard and
  power supply will fit in the case.

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Common Form Factors

• XT
• AT
• Baby AT
• ATX
• Micro ATX
• LPX
• NLX
• BTX

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XT, AT, and BABY AT

• IBM used the XT form factor in 1983 XT was the
  first standardized form factor
• AT was next, slightly larger than XT
• Baby AT was the same size as XT but named
  differently to avoid confusion
• Both AT and Baby AT were used in desktop and
  tower cases.

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XT, AT, and Baby AT Sizes
8.57
12.00
13.04
13.80
XT\BABY AT
AT
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ATX

• Introduced in 1996
• Incompatible with other form factors
• An AT Form Factor power supply would not fit in
  an ATX case.
• An ATX motherboard would not fit in an XT case
• Required a new shape of power supply
• Is similar to Baby AT but turned 90 degrees
  inside the case
• New power supply connector that prevents it from
  being connected incorrectly

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ATX Sizes
12.00
9.60
ATX
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Micro ATX

• Micro ATX follows the ATX form factor
• Improves the overall system design costs through
  a reduction in the physical size of the
  motherboard.
• This was done by reducing the number of I/O
  slots supported on the board.

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LPX

• Designed as a low profile desktop or slim line
  tower case
• No expansion slots directly on the motherboard
• Uses a riser card, typically mounted in the
  center of the board, so expansion cards are
  installed parallel to the motherboard
• Considered a proprietary style used in low cost
  computer systems

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LPX Size
9.00
Bus Riser Card
13.00
LPX
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NLX

• Uses the same riser card principle as LPX
• The edge of the board plugs into the riser card
• NLX is standardized in the industry
• ATX and NLX are the most popular form factors
  used by PC manufacturers

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NLX Sizes
9.00
Plugs into riser card
10.00 to 13.60
NLX
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BTX

• Balanced Technology Extended form factor
• A total break away from the popular and
  dominating ATX form factor.
• BTX was developed to take advantage of
  technologies such as Serial ATA, USB 2.0, and PCI
  Express.
• Physical arrangement of the components on the
  motherboard allows for better airflow throughout
  the system.

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BTX Sizes
10.5
12.8
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How to determine the Form Factor of a computer

• Open the case
• Look for a RISER CARD NLX or LPX
• Does the riser card plug into the motherboard
  (LPX)
• Does the motherboard plug into the riser card
  (NLX)?
• If it does not have a riser card ATX or BTX
• If the machine is older than 7 years it is ATX
• Are components (CPU, RAM) arranged in a line? BTX
• Measure the motherboard and compare it to the
  spec sheets

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Activity

• Fill the Form Factor worksheet
• Sizes, notes, and the How to instructions
• Identify the motherboard form factor in several
  different PC types.