Editing BTX (form factor) (section)

==Enhancements==
*''Low-profile''&nbsp;– With the push for ever-smaller systems, a redesigned backplane that shaves inches off height requirements is a benefit to [[system integrator]]s and enterprises who use [[rack mount]]s or [[blade server]]s.
*''Thermal design''&nbsp;– The BTX layout establishes a straighter path of airflow with fewer obstacles, resulting in better overall cooling capabilities. There is no dedicated CPU fan&nbsp;– instead, a large 12&nbsp;cm case fan is mounted, drawing its air directly from outside the computer and cooling the CPU through an airduct. Another distinct feature of BTX is the vertical mounting of the motherboard on the left-hand side. This results in the graphics card heatsink or fan facing upwards, rather than in the direction of the adjacent expansion card.
*''Structural design''&nbsp;– The BTX standard specifies different locations for hardware mounting points, thereby reducing [[latency (engineering)|latency]] between key components and also reduces the physical strain imposed on the motherboard by heat sinks, capacitors and other components dealing with electrical and thermal regulation. For example, the [[Northbridge (computing)|Northbridge]] and [[Southbridge (computing)|Southbridge]] chips are located near each other and to the hardware they control like CPU, RAM and expansion ports (PS/2, USB, LPT etc.)

===picoBTX===
[[File:BTXformFactor.JPG|right|thumb|BTX form factor motherboard inside a Dell Dimension E520]]
Pico BTX is a [[motherboard]] form factor that is meant to miniaturize the {{convert|12.8|xx|10.5|in|mm|0|abbr=on}} BTX standard. Pico BTX motherboards measure {{convert|8|xx|10.5|in|mm|0|abbr=on}}. This is smaller than many current "micro"-sized motherboards, hence the name  "[[pico-|pico]]". These motherboards share a common top half with the other sizes in the BTX line, but support only one or two expansion slots, designed for half-height or riser card applications.<ref name="Toms Hardware">http://www.tomshardware.com/reviews/beginners-guide-motherboard-selection,1289-5.html {{Dead link|date=February 2022}}</ref>

Other smaller BTX sizes include: [[microBTX]] at {{convert|10.4|xx|10.5|in|mm|0|abbr=on}} and nano BTX at {{convert|8.8|xx|10.5|in|mm|0|abbr=on}}.

{|  class=wikitable
|-
! align=left | Specification
! align=left | Year
! align=left | Dimensions of motherboard
! align=left | Expansion slots
|-
| BTX
| rowspan="4" | 2004
| 10.5 × 12.8 in (266.70 × 325.12&nbsp;mm)
| 7
|-
| microBTX
| 10.5 × 10.4 in (266.70 × 264.16&nbsp;mm)
| 4
|-
| nanoBTX
| 10.5 × 8.8 in (266.70 × 223.52&nbsp;mm)
| 2
|-
| picoBTX
| 10.5 × 8.0 in (266.70 × 203.20&nbsp;mm)
| 1
|}

The heat sink to be attached to the CPU, called "Thermal Module" throughout the official specification, is no longer attached solely to the motherboard, but to the casing itself, so that the inertial load of its mass during a mechanical shock event can no longer damage the motherboard.

The structural interface between the heat sink and the chassis, is defined as 4 mounting holes with the distances of 4.4 × 2.275 in (55.79 × 111.76&nbsp;mm) between one another. And since this attachment means is also required to have a certain stiffness, it is called "Support and Retention Module (SRM)" in the specification.