BTX (form factor)

From Wikipedia, the free encyclopedia

1 Enhancements
- 1.1 Pico BTX
2 Compatibility with ATX products
3 External links
- 3.1 Documentation

Computer form factors	PCB Size (mm)
WTX	356×425
AT	350×305
Baby-AT	330×216
BTX	325×266
ATX	305×244
LPX	330×229
NLX	254×228
microATX	244×244
DTX	244×203
FlexATX	229×191
Mini-DTX	203×170
EBX	203×146
microATX (Min.)	171×171
Mini-ITX	170×170
EPIC (Express)	165×115
Nano-ITX	120×120
COM Express	125×95
ETX / XTX	114×95
Pico-ITX	100×72
PC/104(-Plus)	96×90
microETXexpress
nanoETXexpress
mobile-ITX	75×45

BTX case

BTX (for Balanced Technology Extended) is a form factor for PC motherboards, originally slated to be the replacement for the aging ATX motherboard form factor in late 2004 and early 2005. It has been designed to alleviate some of the issues that arose from using newer technologies (which often demand more power and create more heat) on motherboards compliant with the circa-1996 ATX specification. The ATX and BTX standards were both proposed by Intel. Intel's decision to refocus on low-power CPUs, after suffering scaling and thermal issues with the Pentium 4, has added some doubt to the future of the form factor. The first company to implement BTX was Gateway Inc, followed by Dell. Apple's Mac Pro utilizes the elements of the BTX design system as well but is not BTX compliant. However, future development of BTX retail products by Intel was canceled in September 2006.^[1]

[edit] Enhancements

Low-profile - With the push for ever-smaller systems, a redesigned backplane that shaves inches off height requirements is a benefit to system integrators and enterprises who use rack mounts or blade servers.
Thermal design - The BTX layout establishes a straighter path of airflow with fewer obstacles, resulting in better overall cooling capabilities. A 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 - The BTX standard specifies different locations for hardware mounting points, thereby reducing latency between devices^{[citation needed]} 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 and Southbridge chips are located near each other and to the hardware they control.

[edit] Pico BTX

BTX form factor motherboard inside a Dell Dimension E520.

Pico BTX is a computer motherboard and system form factor. Pico BTX motherboards are relatively small—smaller than current 'micro'-sized motherboards, hence the name 'pico'. They share a common top half with the other sizes in the BTX line, but sport only one or two expansion slots, designed for half-height or riser-card applications.

Intel, as the originator of the form factor, is the primary manufacturer of such boards. As of January 2007, there are very limited numbers of OEM motherboards and cases for Pico BTX. Complete systems are available from Dell, which embraced BTX quickly within its desktop product line, and appears to use Pico BTX boards in its smallest machines, though no claims are made by Dell in their marketing materials.

[edit] Compatibility with ATX products

The BTX form factor is largely incompatible with the ATX form factor. The only area where this doesn't fully apply is in power supply support. ATX power supplies can be used with regular or full-sized BTX motherboards. Neither the power connectors nor the direction of airflow from the power supply fan has been changed.