Asus P5Q-EM - Manual (Page 54)

1-42 Chapter 1: Product introduction
12. ATX power connectors (24-pin EATXPWR, 4-pin ATX12V)
These connectors are for ATX power supply plugs. The power supply plugs
are designed to fit these connectors in only one orientation. Find the proper
orientation and push down firmly until the connectors completely fit.
• For a fully configured system, we recommend that you use a power supply
unit (PSU) that complies with ATX 12 V Specification 2.0 (or later version)
and provides a minimum power of 400 W.
• Do not forget to connect the 4-pin ATX12V power plug; otherwise, the
system will not boot.
• Use of a PSU with a higher power output is recommended when
configuring a system with more power-consuming devices. The system
may become unstable or may not boot up if the power is inadequate.
• If you are uncertain about the minimum power supply requirement for your
system, refer to the Recommended Power Supply Wattage Calculator
at http://support.asus.com/PowerSupplyCalculator/PSCalculator.
aspx?SLanguage=en-us for details.