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MoboCop · 11-12-2004 · Category: Tech-planations



Intel has collaborated with the Desktop Computing industry to create an evolutionary step in the desktop computer form factor. Balanced Technology Extended (BTX) integrates cost-effective engineering and design strategies for power dissipation, structural integrity, acoustic performance, and motherboard design into a scalable form factor. The BTX specification was introduced at Intel Developers Forum in Fall, 2003. Intel and others in the desktop computing industry plan to start offering products based on this innovative new form factor starting in Q3, 2004.


BTX Thermal Modules

In order to produce the in-line airflow which is the key to the many benefits of this new specification, the BTX form factor utilizes a new thermal module design, which combines a fan, heatsink and duct. There are two sizes specified.

  • Type I (Standard height): Designed to support a broad range of system sizes from full towers down to small form factor (10 liters and higher).
  • Type II (Low Profile): Designed to support ultra-thin, ultra-small form-factor systems (6-9 liters).

Detailed information on thermal module size is available in the BTX Specification

BTX-based Motherboards

The BTX-based motherboard layout differs significantly from ATX/microATX, and requires designs built specifically for BTX. BTX also allows for multiple board sizes utilizing a common core:

  • picoBTX: maximum width 203.20 mm, up to 1 add-in card slot
  • microBTX: maximum width 264.16 mm, up to 4 add-in card slots
  • BTX: maximum width 325.12 mm, up to 7 add-in card slots

BTX-based Chassis

Because of the changes in motherboard layout, the new form factor will require unique chassis designed specifically for BTX. It will be critical to select a chassis that supports the chosen board size. A BTX-compatible chassis will require built-in features to attach the Support and Retention Module (defined below). Additionally, a Thermal Module Interface may be required. This is a ducting feature connecting the front of the Thermal Module to a front vent. It is needed to ensure that airflow exiting the Thermal Module cannot re-circulate and re-enter the Thermal Module Interface opening.

Support and Retention Module (SRM)

The SRM is a metal plate that is assembled to the chassis beneath the motherboard to provide structural support for the motherboard and retention for the thermal module. The SRM is expected to be shipped with BTX-compatible chassis.

BTX-compatible Power Supplies

For large systems (20L and higher), standard ATX12V power supplies may be used.
For mini-tower systems (15L to 22L), standard SFX12V power supplies may be used. To support smaller systems, two new power supply designs will be offered:
For use with small form-factor system designs (10-15L in total system volume).
For use with ultra-small form-factor system designs (6-9L in total system volume).

Ingredients that are not BTX-specific

Many of the ingredients currently used for ATX-based systems are also compatible with BTX-based systems. These cross-platform ingredients include:

  • Memory
  • Hard Drives
  • Optical Drives
  • Floppy (and other 3.5) Drives
  • Add-in cards (PCI, PCI-Express)
  • ATX12V Power Supplies (for 20L and larger systems)
  • SFX12V Power Supplies (for 15-22L systems)


  1. Motherboard Form Factors
  2. AT
  3. Baby AT
  4. ATX
  5. Mini-ATX
  6. microATX
  7. FlexATX
  8. LPX
  9. Mini LPX
  10. NLX
  11. BTX
  12. picoBTX
  13. microBTX
  14. PC/XT
  15. Mini-ITX

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