Technical Reference
57
2.5 Electrical Considerations
2.5.1 Power Supply Considerations
CAUTION
The +5 V standby line from the power supply must be capable of providing adequate
+5 V standby current. Failure to do so can damage the power supply. The total
amount of standby current required depends on the wake devices supported and
manufacturing options.
Additional power required will depend on configurations chosen by the integrator.
The power supply must comply with the indicated parameters of the ATX form factor
specification.
• The potential relation between 3.3 V DC and +5 V DC power rails
• The current capability of the +5 VSB line
• All timing parameters
• All voltage tolerances
For example, for a high power system consisting of a supported 95 W processor (see
Section 1.4 on page 17 for a list of supported processors), 4 GB DDR3 RAM, one high
end video card, one hard disk drive, one optical drive, and all board peripherals
enabled, the minimum recommended power supply is 460 W. Table 33 lists possible
recommended power supply current rail values.
Table 33. Recommended Power Supply Current Values (High Power)
Output Voltage 3.3 V 5 V 12 V1 12 V2 -12 V 5 VSB
Current 22 A 20 A 20 A 20 A 0.3 A 2.5 A
For example, for a low power system consisting of a supported 45 W processor (see
Section 1.4 on page 17 for a list of supported processors), 2 GB DDR3 RAM, Onboard
Graphics, one SSD, one optical drive, and no extra onboard peripherals enabled, the
minimum recommended power supply is a 320 W. Table 34 lists possible
recommended power supply current rail values. Note: If the correct power supply and
sy
st
em configuration is used, a smaller power supply will work.
Table 34. Recommended Power Supply Current Values (Low Power)
Output Voltage 3.3 V 5 V 12 V1 12 V2 -12 V 5 VSB
Current 20 A 20 A 15 A 15 A 0.3 A 1.5 A
For information about Refer to
Selecting an appropriate power supply http://support.intel.com/support/motherboards/desktop/sb
/CS-026472.htm