Hardware Reference
In-Depth Information
Finally,amorerecentvariationonSFXiscalledthe
PS3 form factor
,definedinAppendix
E of the SFX12V specification. Although defined as part of SFX12V, the PS3 form factor
is actually a shortened version of ATX12V and is generally used in systems with mi-
croATX chassis and motherboards that require higher power output than the smaller SFX
variants can supply (see
Figure 18.6
)
.
Figure 18.6
PS3 (SFX/SFX12V) power supply with internal 80mm fan.
SFX12V power supplies are specifically designed for use in small systems containing a
limited hardware and limited upgradeability. Most SFX supplies are designed to provide
80-300 watts of continuous power in four voltages (+5V, +12V, −12V, and +3.3V). This
amount of power has proven to be sufficient for a small system with a processor, an
AGP or PCI Express x16 interface, up to four expansion slots, and three peripheral
devices—such as hard drives and optical drives.
Although Intel designed the SFX12V power supply specification with the microATX and
FlexATX motherboard form factors in mind, SFX is a wholly separate standard that is
compliant with other motherboards as well. For example, the PS3 variant of SFX12V can
replace standard ATX12V power supplies as long as the output capabilities and provided
connectors match the system requirements. SFX power supplies use the same 20-pin or
24-pinconnectorsdefinedintheATX/ATX12VstandardsandincludeboththePower_On
and5V_Standbyoutputs.SFX12Vpowersuppliesaddthe4-pin+12VconnectorforCPU
power, just as ATX12V supplies do. Whether you will use an ATX- or SFX-based power
supply in a given system depends more on the case or chassis than the motherboard. Each
