Computer form factors Name PCB size (mm) WTX 356 × 425 AT 350 × 305 Baby-AT 330 × 216 BTX 325 × 266 ATX 305 × 244 EATX (Extended) 305 × 330 LPX 330 × 229 microBTX 264 × 267 NLX 254 × 228 Ultra ATX 244 × 367 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 ESM 149 × 71 Nano-ITX 120 × 120 COM Express 125 × 95 ESMexpress 125 × 95 ETX/XTX 114 × 95 Pico-ITX 100 × 72 PC/104 (-Plus) 96 × 90 ESMini 95 × 55 Qseven 70 × 70 mobile-ITX 60 × 60 CoreExpress 58 × 65
ATX (Advanced Technology eXtended) is a motherboard form factor specification developed by Intel in 1995 to improve on previous de facto standards like the AT form factor. It was the first big change in computer case, motherboard, and power supply design in many years, improving standardization and interchangeability of parts. The specification defines the key mechanical dimensions, mounting point, I/O panel, power and connector interfaces between a computer case, a motherboard, and a power supply. With the improvements it offered, including lower costs, ATX overtook AT completely as the default form factor for new systems within a few years. ATX addressed many of the AT form factor's annoyances that had frustrated system builders. Other standards for smaller boards (including microATX, FlexATX and mini-ITX) usually keep the basic rear layout but reduce the size of the board and the number of expansion slot positions. In 2003, Intel announced the BTX standard, intended as a replacement for ATX. As of 2009[update], the ATX form factor remains a standard for do-it-yourselfers; BTX has however made inroads into pre-made systems.This was designed to solve the problems in BAT and LPX Motherboards
The official specifications were released by Intel in 1995, and have been revised numerous times since, the most recent being version 2.3, released in 2007.
A full-size ATX board is 12 × 9.6 in (305 × 244 mm). This allows many ATX form factor chassis to accept microATX boards as well.
On the back of the system, some major changes were made. The AT standard had only a keyboard connector and expansion slots for add-on card backplates. Any other onboard interfaces (such as serial and parallel ports) had to be connected via flying leads to connectors which were mounted either on spaces provided by the case or brackets placed in unused expansion slot positions. ATX allowed each motherboard manufacturer to put these ports in a rectangular area on the back of the system, with an arrangement they could define themselves, though a number of general patterns depending on what ports the motherboard offers have been followed by most manufacturers. Cases are usually fitted with a snap-out panel, also known as an I/O plate or I/O shield, in one of the common arrangements. If necessary, I/O plates can be replaced to suit a motherboard that is being fitted; the I/O plates are usually included with motherboards not designed for a particular computer. The computer will operate correctly without a plate fitted, although there will be open gaps in the case and the EMI/RFI screening will be compromised. Panels were made that allowed fitting an AT motherboard in an ATX case.
ATX also made the PS/2-style mini-DIN keyboard and mouse connectors ubiquitous. AT systems used a 5-pin DIN connector for the keyboard, and were generally used with serial port mice (although PS/2 mouse ports were also found on some systems). Many modern motherboards are phasing out the PS/2-style keyboard and mouse connectors in favor of the more modern Universal Serial Bus. Other legacy connectors that are slowly being phased out of modern ATX motherboards include 25-pin parallel ports and 9-pin RS-232 serial ports. In their place are onboard peripheral ports such as Ethernet, FireWire, eSATA, audio ports (both analog and S/PDIF), video (analog D-sub, DVI, or HDMI), and extra USB ports.
Several ATX-derived form factors have been specified that use the same power supply, mountings and basic back panel arrangement, but set different standards for the size of the board and number of expansion slots. The two most popular are the Standard (6 slots) and Micro ATX (4 slots) sizes. Here length refers to the distance along the external connector edge
width length color in image FlexATX 9 in (229 mm) 7.5 in (191 mm) microATX and EmbATX 9.6 in (244 mm) 9.6 in (244 mm) Mini ATX 11.2 in (284 mm) 8.2 in (208 mm) Standard ATX 12 in (305 mm) 9.6 in (244 mm) EATX (extended ATX) 12 in (305 mm) 13 in (330 mm) EEATX (enhanced extended ATX) 13.68 in (347 mm) 13 in (330 mm) WTX (workstation ATX) 14 in (356 mm) 16.75 in (425 mm)
Ultra ATX, XL-ATX
In 2008, Foxconn unveiled a Foxconn F1 motherboard prototype, which has the same width as a standard ATX motherboard, but an extended 14.4" length to accommodate 10 slots. The firm called the new "form factor" for this motherboard "Ultra ATX" in its CES 2008 showing. Also unveiled during the January 2008 CES was the Lian Li Armorsuit PC-P80 case with 10 slots designed for the motherboard.
Unlike Ultra-ATX which was fully defined by a single company, XL-ATX does not yet have established dimensional standards. In April 2010, Gigabyte Technology announced its 12.8" long by 9.6" wide GA-890FXA-UD7 motherboard that allowed all seven slots to be moved downward by one slot position. The added length could have allowed placement of up to eight expansion slots, but the top slot position is vacant on this particular model. Meanwhile, EVGA Corporation had already released a 13.5" long by 10.3" wide "XL-ATX" motherboard as its EVGA X58 Classified 4-Way SLI. EVGA's version of XL-ATX has room for up to nine expansion slots, but the top two positions are vacant. Note that even though both of these boards have room for extra expansion slots, neither makes use of that extra room for card placement. In Q2/2010 Gigabyte launched another XL-ATX Mainboard with model number GA-X58A-UD9, but it also only implements 7 PCI-Express x16 Slots (the extra space from XL-ATX form factor seems to be needed for chipset cooling).
In 2010, EVGA Corporation released a new motherboard, the "Super Record 2", or SR-2, whose size surpasses that of the "EVGA X58 Classified 4-Way SLI". The new board is designed to accommodate two Dual QPI LGA1366 slot CPUs (e.g. Intel Xeon), similar to that of the Intel "SkullTrail" motherboard that could accommodate two Intel Core 2 Quad processors, and has a total of seven PCI-E slots and 12 DDR3 RAM slots. The new form factor is dubbed "HPTX", and is 13.6 by 15 inches (34.5 cm by 38.1 cm).
The ATX specification requires the power supply to produce three main outputs, +3.3 V, +5 V and +12 V. Low-power −12 V and 5 VSB (standby) supplies are also required. A −5 V output was originally required because it was supplied on the ISA bus, but it became obsolete with the removal of the ISA bus in modern PCs and has been removed in later versions of the ATX standard.
Originally the motherboard was powered by one 20-pin connector. An ATX power supply provides a number of peripheral power connectors, and (in modern systems) two connectors for the motherboard: a 4-pin auxiliary connector providing additional power to the CPU, and a main 24-pin power supply connector, an extension of the original 20-pin version.
24-pin ATX12V 2.x power supply connector
(20-pin omits the last four: 11, 12, 23 and 24)
Color Signal Pin Pin Signal Color Orange +3.3 V 1 13 +3.3 V Orange +3.3 V sense Brown Orange +3.3 V 2 14 −12 V Blue Black Ground 3 15 Ground Black Red +5 V 4 16 Power on Green Black Ground 5 17 Ground Black Red +5 V 6 18 Ground Black Black Ground 7 19 Ground Black Grey Power good 8 20 Reserved N/C Purple +5 V standby 9 21 +5 V Red Yellow +12 V 10 22 +5 V Red Yellow +12 V 11 23 +5 V Red Orange +3.3 V 12 24 Ground Black
- Pins 8, and 16 (shaded) are control signals, not power:
- Power on is pulled up to +5 V by the PSU, and must be driven low to turn on the PSU.
- Power good is low when other outputs have not yet reached, or are about to leave, correct voltages.
- Pin 13 supplies +3.3 V power and also has a second thinner wire for remote sensing.
- Pin 20 (formerly −5 V, white wire) is absent in current power supplies; it was optional in ATX and ATX12V ver. 1.2, and deleted as of ver. 1.3.
- The right-hand pins are numbered 11–20 in the 20-pin version.
Four wires have special functions:
- PS_ON# or Power on is a signal from the motherboard to the power supply. When the line is connected to ground (by the motherboard), the power supply turns on. It is internally pulled up to +5 V inside the power supply.
- PWR_OK or Power good is an output from the power supply that indicates that its output has stabilized and is ready for use. It remains low for a brief time (100–500 ms) after the PS_ON# signal is pulled low.
- +5 VSB or +5 V standby supplies power even when the rest of the supply lines are off. This can be used to power the circuitry that controls the Power On signal.
- +3.3 V sense should be connected to the +3.3 V on the motherboard or its power connector. This connection allows for remote sensing of the voltage drop in the power supply wiring.
Generally, supply voltages must be within ±5% of their nominal values at all times. The little-used negative supply voltages, however, have a ±10% tolerance. There is a specification for ripple in a 10 Hz–20 MHz bandwidth:
Supply [V] Tolerance Range (min. to max.) Ripple (p. to p. max.) +5 VDC ±5% (±0.25 V) +4.75 V to +5.25 V 50 mV −5 VDC ±10% (±0.50 V) –4.50 V to –5.50 V 50 mV +12 VDC ±5% (±0.60 V) +11.40 V to +12.60 V 120 mV −12 VDC ±10% (±1.2 V) –10.8 V to –13.2 V 120 mV +3.3 VDC ±5% (±0.165 V) +3.135 V to +3.465 V 50 mV +5 VSB ±5% (±0.25 V) +4.75 V to +5.25 V 50 mV
ATX power supplies generally have the dimensions of 6 × 3.4 × 5.5 (inches) and in metric 150 mm × 86 mm × 140 mm and share a common mounting layout of four screws arranged on the back side of the unit.
Main changes from AT design
AT-style computer cases had a power button that was directly connected to the system computer power supply (PSU). The general configuration was a double-pole latching mains voltage switch with the four pins connected to wires from a four-core cable. The wires were either soldered to the power button (making it difficult to replace the power supply if it failed) or blade receptacles were used.
An ATX power supply does not directly connect to the system power button, allowing the computer to be turned off via software. However, many ATX power supplies have a manual switch on the back to ensure the computer is truly off and no power is being sent to the components. With this switch on, energy still flows to the components even when the computer appears to be "off." This is known as soft-off or standby and can be used for remote wake up through Wake-on-Ring or Wake-on-LAN, but is generally used to power on the computer through a front switch.
Power connection to the motherboard
The power supply's connection to the motherboard was changed from the older AT standard; ATs had two similar connectors that could be accidentally interchanged by forcing the different keyed connectors into place, usually causing short-circuits and irreversible damage to the motherboard (the rule of thumb for safe operation was to connect the side-by-side connectors with the black wires together). ATX used one large, keyed connector which could not be connected wrongly. The new connector also provides a 3.3 volt source, removing the need for motherboards to derive this voltage from the 5V rail. Some motherboards, particularly those manufactured after the introduction of ATX but while AT equipment was still in use, supported both AT and ATX PSUs.
If using an ATX PSU for other purposes than powering an ATX motherboard, power can be fully turned on (it is always partly on to operate "wake-up" devices) by shorting the "power-on" pin on the ATX connector (pin 16, green wire) to a black wire (ground), which is what the power button on an ATX system does. At least the specified minimum load required by the PSU should be present; the standard does not specify operation without load, and a conforming PSU may shut down, output incorrect voltages, or otherwise malfunction, but will not be hazardous or damaged.
The original ATX specification called for a power supply to be located near to the CPU with the power supply fan drawing in cooling air from outside the chassis and directing it onto the processor. It was thought that in this configuration, cooling of the processor would be achievable without the need of an active heatsink. This recommendation was removed from later specifications; modern ATX power supplies usually exhaust air from the case.
ATX power supply revisions
ATX, introduced in late 1995, defined three types of power connectors:
- 4-pin "Molex connector" — transferred directly from AT standard: +5 V and +12 V for P-ATA hard disks, CD-ROMs, 5.25 inch floppy drives and other peripherals.
- 4-pin Berg floppy connector — transferred directly from AT standard: +5 V and +12 V for 3.5 inch floppy drives and other peripherals.
- 20-pin Molex Mini-fit Jr. main motherboard connector — new to the ATX standard.
- A supplemental 6-pin AUX connector providing additional 3.3 V and 5 V supplies to the motherboard, if needed. This was used to power the CPU in motherboards with CPU voltage regulator modules which required 3.3 volt and/or 5 volt rails and could not get enough power through the regular 20-pin header.
The power distribution specification defined that most of the PSU's power should be provided on 5 V and 3.3 V rails, because most of the electronic components (CPU, RAM, chipset, PCI, AGP and ISA cards) used 5 V or 3.3 V for power supply. The 12 V rail was only used by fans and motors of peripheral devices (HDD, FDD, CD-ROM, etc.).
The original ATX power supply specification was little revised until 2000.
While designing the Pentium 4 platform in 1999/2000, the standard 20-pin ATX power connector was found insufficient to meet increasing power-line requirements; the standard was significantly revised into ATX12V 1.0 (ATX12V 1.x is sometimes inaccurately called ATX-P4). ATX12V 1.x was also adopted by AMD Athlon XP and Athlon 64 systems.
The main changes and additions in ATX12V 1.0 (released in February 2000) were:
- Increased the power on the 12 V rail (power on 5 V and 3.3 V rails remained mostly the same).
- An extra 4-pin mini fit JR (Molex 39-01-2040), 12-volt connector to power the CPU. Formally called the +12 V Power Connector, this is commonly referred to as the P4 connector because this was first needed to support the Pentium 4 processor.
Before the Pentium 4, processors were generally powered from the 5V rail. Later processors operate at much lower voltages, typically around 1 V, and some draw over 100 A. It is infeasible to provide power at such low voltages and high currents from a standard system power supply, so the Pentium 4 established the practice of generating it with a DC-to-DC converter on the motherboard next to the processor, powered by the 4-pin 12V connector.
This is a minor revision from August 2000. The power on the 3.3 V rail was slightly increased, and other lesser changes made.
A relatively minor revision from January 2002. The only significant change was that the −5 V rail was no longer required (it became optional). This voltage was used only on some old systems with certain ISA add-on cards.
Introduced in April 2003 (a month after 2.0). This standard introduced some changes, mostly minor. Some of them are:
- Slightly increased the power on 12 V rail.
- Defined minimal required PSU efficiencies for light and normal load.
- Defined acoustic levels.
- Introduction of Serial ATA power connector (but defined as optional).
- The −5 V rail is prohibited.
ATX12V 2.x brought a very significant design change regarding power distribution. On analyzing the then-current PC architecture's power demands it was determined that it would be much cheaper and more practical to power most PC components from 12 V rails, instead of from 3.3 V and 5 V rails.
The above conclusion was incorporated in ATX12V 2.0 (introduced in February 2003), which defined quite different power distribution from ATX12V 1.x:
- The main ATX power connector was extended to 24 pins. The extra four pins provide one additional 3.3 V, 5 V and 12 V circuit.
- The 6-pin AUX connector from ATX12V 1.x was removed because the extra 3.3 V and 5 V circuits which it provided are now incorporated in the 24-pin main connector.
- Most power is now provided on 12 V rails. The standard specifies that two independent 12 V rails (12 V2 for the 4 pin connector and 12 V1 for everything else) with independent overcurrent protection are needed to meet the power requirements safely (some very high power PSUs have more than two rails, recommendations for such large PSUs are not given by the standard).
- The power on 3.3 V and 5 V rails was significantly reduced.
- The power supply is required to include a Serial ATA power cable.
- Many other specification changes and additions.
This is a minor revision from June 2004. An errant reference for the -5V rail was removed. Other minor changes were introduced.
This is a minor revision from March 2005. The power was slightly increased on all rails. Efficiency requirements changed. Added 6-pin connector for PCIe graphics cards, that aids the PCIe slot in the motherboard, delivering 75 watts.
Another minor revision. Added 8-pin connector for PCIe graphics cards, that delivers another 150 watts.
Effective March 2007 and current as of 2011[update]. Recommended efficiency was increased to 80% (with at least 70% required), and the 12 V minimum load requirement was lowered. Higher efficiency generally results in less power consumption (and less waste heat), and the 80% recommendation brings supplies in line with new Energy Star 4.0 mandates. The reduced load requirement allows compatibility with processors that draw very little power during startup. The absolute over-current limit of 240VA per rail was removed, allowing 12V lines to provide more than 20A per rail.
ATX power supply derivatives
SFX is merely a form factor for a power supply casing and the power specifications are almost identical. Thus, an SFX power supply is mostly interchangeable with the ATX power supply. The only difference is that the SFX specifications do not require the -5V rail. Since -5V is required only by some ISA bus expansion cards, this is not an issue with modern hardware and decreases productions costs. As a result, ATX pin 20, which carried -5V, is absent in current power supplies; it was optional in ATX and ATX12V ver. 1.2, and deleted as of ver. 1.3.
SFX has dimensions of 100 x 125 x 63.5 (width x depth x height in mm) with 60 mm fan. Optional 80 or 40 mm fan replacement increases or decreases the height of the unit.
Another small form factor power supply with standard ATX specification connectors. Generally 5.75 in × 3.25 in × 2.5 in (D) × (W) × (H) (146 mm x 83 mm x 64 mm)
Provides a WTX style motherboard connector which is incompatible with the standard ATX motherboard connector.
This is an ATX12V power supply derivative made by AMD to power its Athlon MP (dual processor) platform. It was used only on high-end Athlon MP motherboards. It has a special 8-pin supplemental connector for motherboard, so an AMD GES PSU is required for such motherboards (those motherboards will not work with ATX(12 V) PSUs).
EPS12V is defined in SSI, and used primarily by SMP/multi-core systems such as Core 2, Core i7, Opteron and Xeon. It has a 24-pin main connector (same as ATX12V v2.x), an 8-pin secondary connector, and an optional 4-pin tertiary connector. Rather than include the extra cable, many power supply makers implement the 8-pin connector as two combinable 4-pin connectors to ensure backwards compatibility with ATX12V motherboards.
Recent specification changes and additions
High-performance video card power demands dramatically increased during the 2000s, and some high-end graphics cards have power demands that exceed AGP or PCIe slot capabilities. For these cards supplementary power was delivered through a standard 4-pin peripheral or floppy power connector. Midrange and high-end PCIe graphics cards manufactured after 2004 typically use a standard 6 or 8-pin PCIe power connector directly from the PSU.
Interchanging old/new systems with old/new PSUs
Although the ATX power supply specifications are mostly vertically compatible in both ways (both electrically and physically), there are potential issues with mixing old motherboards/systems with new PSUs, and vice versa. The main issues to consider are the following:
- The power distribution biases across 3.3 V, 5 V, and 12 V rails are very different between older and newer ATX PSU designs, as well as between older and newer PC system designs.
- Older PSUs may not have connectors which are required for newer PC systems to properly operate.
- Newer systems generally require larger power supplies than older systems.
This is a practical guidance what to mix and what not to mix:
- Older systems (until Pentium 4 and Athlon XP platforms) were designed to draw most power from 5 V and 3.3 V rails.
- Because of the DC-DC converters on the motherboard that convert 12 V to the low voltages required by the Intel Pentium 4 and AMD Athlon XP (and subsequent) processors, such systems draw most of their power from the 12 V rail.
- Original ATX PSUs have power distribution designed for pre-P4/XP PCs. They lack the supplemental 4-pin 12-volt CPU power connector, so they most likely cannot be used with P4/XP or newer motherboards. Adapters do exist but power drain on the 12 V rail must be checked very carefully. There is a chance it can work without connecting the 4-pin 12 V connector, but caution is advised.[dead link]
- ATX12V 1.x PSUs have power distribution designed for P4/XP PCs, but they are also greatly suitable for older PCs, since they give plenty of power (relative to old PCs' needs) both on 12 V and on 5 V/3.3 V. It is not recommended to use ATX12V 1.x PSUs on ATX12V 2.x motherboards because those systems require much more power on 12 V, and much less on 3.3 V/5 V than ATX12V 1.x PSUs provide.
- ATX12V 2.x PSUs have power distribution designed for late P4/XP PCs and for Athlon 64 and Core Duo PCs. They can be used with earlier P4/XP PCs, but the power distribution will be significantly suboptimal, so a more powerful ATX12V 2.0 PSU should be used to compensate for that discrepancy. ATX12V 2.x PSUs can also be used with pre-P4/XP systems, but the power distribution will be greatly suboptimal (12 V rails will be mostly unused, while the 3.3 V/5 V rails will be overloaded), so this is not recommended.
- Systems that use an ISA bus require ATX/ATX12V 1.2 or earlier because the ISA bus requires a −5 V power rail unless the board provides a DC to DC converter that supplies −5 V. ATX/ATX12V 1.3 and later prohibit the −5 V rail so power supplies built to these versions are usually unsuitable for ISA systems.
Not all computers use standard, interchangeable ATX power supplies. In particular, some proprietary brand-name machines and high-end workstation and server designs do not, and require an exactly-matching power supply unit.
Issues with Dell power supplies
Older Dell computers, particularly those from the Pentium II and III lines, are notable for using proprietary power wiring on their power supplies and motherboards. While the motherboard connectors appear to be standard ATX, and will actually fit a standard power supply, they are not compatible. Not only have wires been switched from one location to another, but the number of wires for a given voltage have been changed. Thus, the pins cannot simply be rearranged.
The change affects not only 20-pin ATX connectors, but also auxiliary 6-pin connectors. Modern Dell systems might use standard ATX connectors. Dell PC owners should be careful when attempting to change Dell motherboards and power supplies from the original setup, as it can cause damage to the power supply or other components. If the power supply color coding on the wiring does not match ATX standards, then it is probably proprietary. Wiring diagrams for Dell systems are usually available on Dell's support page.
To determine if a Dell PC has this propriety ATX (non industrial standard), view the power pin layout in the on-line dell 'SERVICE' manual (not user manual) and compare it with the ATX pin diagram above. A more reliable method is to measure the voltages on the connector.
DELL motherboard ATX type power supply connector pinout
(This non-standard wiring is used in DELL Pentium II and Pentium III systems)
Color Signal Pin Pin Signal Color Red +5 V 1 11 PS_On Grey Black Ground 2 12 Ground Black Red +5 V 3 13 Ground Black Black Ground 4 14 Ground Black Orange Power good 5 15 −5 V White Purple +5 VSB (standby) 6 16 +5 V Red Yellow +12 V 7 17 +5 V Red Blue −12 V 8 18 +5 V Red Black Ground 9 19 - KEY (blank) Black Ground 10 20 +5 V Red
- 18 AWG is recommended for all wires except pin 11, which should be 22 AWG. For 300 W configurations 16 AWG is recommended.
- Note: some Dell power supplies do not have the −5 V (white wire), (2002 v1.2 made optional, 2004 v2.01 removed from specification)
- ^ "form factors.org - ATX Motherboard". http://www.formfactors.org/FFDetail.asp?FFID=1&CatID=1. Retrieved 2008-04-20.
- ^ Foxconn F1 Motherboard Prototype
- ^ http://www.tomshardware.com/news/ces-foxconn-x48-shimano,4677.html
- ^ Lian Li Armorsuit PC-P80R Spider Edition
- ^ The New 4-Way SLI Platform Has Arrived!
- ^ EVGA Corporation Super Record 2
- ^ "ATX Specification Version 2.1". http://www.formfactors.org/developer/specs/atx2_1.pdf.
- ^ a b "ATX Specification Version 2.2". http://www.formfactors.org/developer%5Cspecs%5Catx2_2.pdf. 090503 formfactors.org
- ^ "How to Convert a Computer ATX Power Supply to a Lab Power Supply (with video) - wikiHow". http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply. 090503 wikihow.com
- ^ "PCGuide - Ref - Power Supply - Functions". http://www.pcguide.com/ref/power/sup/func_SoftPower.htm. 090503 pcguide.com
- ^ "PC peripheral power connector pinout and signals @ pinouts.ru". http://pinouts.ru/Power/BigPower_pinout.shtml. 090514 pinouts.ru
- ^ "PC floppy power connector pinout and signals @ pinouts.ru". http://pinouts.ru/Power/SmallPower_pinout.shtml. 090514 pinouts.ru
- ^ "AT / ATX12V Power Supply Design Guide Version 1.1" (pdf). Intel Corporation. August 2000. pp. 28. Archived from the original on 2011-03-11. http://www.webcitation.org/query?url=http%3A%2F%2Fwww.formfactors.org%2Fdeveloper%255Cspecs%255CATX_ATX12V_PS_1_1.pdf&date=2011-03-11. Retrieved 2011-03-11.
- ^ Design Guide for Desktop Platform Form Factors, Intel Corp
- ^ 3DGameMan.com Question/Answer: ATX 12V 2.2 vs. ATX 12V 2.3. (video)
- ^ SFX Form Factor
- ^ http://www.neoseeker.com/Hardware/faqs/kb/12,17.html
- ^ http://support.euro.dell.com/support/edocs/systems/
- ^ "DELL ATX motherboard Power Supply connector pinout". http://pinouts.ru/Power/dell_atxpower_pinout.shtml.
- ATX Motherboard Specification, v2.2
- ATX Riser Card Specification Revision 1.0
- Power supply information
- Power Supply Form Factors
- ATX12V Power Supply Design Guide, v2.01
- ATX12V Power Supply Design Guide, v2.2
- Power Supply Design Guide for Desktop Platform Form Factors (ATX12V specification v2.3)
- Power Supply Design Guide for Desktop Platform Form Factors Revision 1.2
- EPS12V Power Supply Design Guide Version 2.92
- EPS12V Power Supply Design Guide, v2.91
- EPS12V Power Supply Design Guide, v2.0
- Various power supply cables and connectors
- A short history of power supply voltage rails
- ATX power supply connectors with pinouts
- More ATX power supply connectors with pinouts
- ATX Power Supply Terminology
- Pins 8, and 16 (shaded) are control signals, not power:
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