Balanced Technology Extended (BTX) Channel Resource Center

Ingredients for Balanced Technology Extended (BTX)-based Systems

Building a Balanced Technology Extended (BTX)-compliant system will require some new ingredients, designed specifically to support the BTX form-factor. Below is an introduction to the ingredients that differ from those typically supporting the ATX specification.

BTX Thermal Modules
BTX-based Motherboards
BTX-based Chassis
Support and Retention Module
BTX-compatible Power Supplies
Ingredients that are not BTX-specific

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 Balanced Technology Extended (BTX) Interface Specification which is available for download at www.formfactors.org.

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.
nanoBTX: maximum width 223.53 mm, up to 2 add-in card slots
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

ATX12V:	For large systems (20L and higher), standard ATX12V power supplies may be used.
SFX12V:	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:
CFX12V:	For use with small form-factor system designs (10-15L in total system volume).
LFX12V:	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)

Support for these various ingredients may depend on chassis configuration. Check with your BTX-based chassis supplier for details.