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Builder’s Guide for AMD Opteron™ Processor-Based
Servers and Workstations
30925 Rev. 3.04 February 2004
32 Hardware Considerations
Chapter 5
In order to have a reliable and cost-effective system, system builders should calculate the power
requirements for the intended configuration.
Note: System builders should refer to the motherboard manual to check the type of power
connector and type of power supply the motherboard uses. The motherboard, power supply,
and case must be mechanically and electrically compatible.
5.2.2 Calculating System Power Consumption
The total combined wattage for the system configuration must be less than the output of the power
supply used. Overall current usage limitation on the power supply should not exceed a combined
system power output for the +5-V and +3.3-V outputs.
Use the power worksheets given in Table 1 on page 32 and Table 2 on page 33 to calculate the
system power consumption. For current and voltage requirements of add-in boards and
peripherals, refer to your vendor’s documents. The current draw on each voltage tap should be
included with the documentation from the motherboard vendor.
In Power Worksheet 1—Component Power list the peak current for each board and device
applicable in the appropriate voltage level column. Add the currents in each column, then go to
Power Worksheet 2—Total Watts.
Table 1. Power Worksheet 1—Component Power
Device
Item
Qty
Maximum Current at Each Voltage Level
+3.3 V +5 V +12 V –12 V 5 VSB
Motherboard w/on-board devices
System fan
Processor fan
Memory module
AGP VGA card
PCI modem card
PCI sound card
PCI NIC card
PCI SCSI card
Other PCI card/Bus card
PCI RAID card
IDE hard drive
SCSI hard drive