Asus P4B-LX - Manual (Page 40)

2-20 Chapter 2: Hardware information
5. Power supply connectors (20-pin ATXPWR, 4-pin ATX+12V)
These connectors connect to an ATX 12V power supply. The plugs from
the power supply are designed to fit these connectors in only one
orientation. Find the proper orientation and push down firmly until the
connectors completely fit.
In addition to the 20-pin ATXPWR connector, this motherboard requires
that you connect the 4-pin ATX +12V power plug to provide sufficient
power to the CPU.
Figure 2-25 Power Supply Connectors
Make sure that your ATX 12V power supply can provide 8A on the
+12V lead and at least 1A on the +5-volt standby lead (+5VSB). The
minimum recommended wattage is 230W, or 300W for a fully
configured system. The system may become unstable and may
experience difficulty powering up if the power supply is inadequate.
P4B-LX
P4B-LX ATX Power Connectors
ATXPWR
ATX12V
+12V DC COM
+12V DC COM
Pin 1
Pin 1
+3.3VDC
-12.0VDC
COM
PS_ON#
COM
COM
COM
-5.0VDC
+5.0VDC
+5.0VDC
PWR_OK
+12.0VDC
+3.3VDC
+3.3VDC
COM
+5.0VDC
COM
+5.0VDC
COM
+5VSB