AC450NX Rack Server System Product Guide
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Calculating Power Usage

Use the worksheets in Tables 20-4 and 20-5 to calculate the total DC power used by your server
configuration.
The documentation that comes with each add-in device should specify its current and voltage
requirements.
To calculate the total combined wattage for your server, do this:
1. List the current for each board and device in the appropriate voltage level column in
Table 20-4.
2. Add the currents in each column of Table 20-4, and enter the total current for each column in
Table 20-5.
3. Multiply the voltage by the total current to get the total wattage for each voltage level.
4. Add the total wattage for each voltage level to arrive at a total combined power usage on the
power supply.
Table 20-4. Worksheet for Calculating DC Power Usage
Current (maximum) at voltage levels:
Device +3.3 V + 5V stby +5 V +12 V -12 V
PHP I/O baseboard 5 A 0.65 A 4.32 A 0.05 A 0 A
16-bit ISA slot, J3B
32-bit primary PCI slot 1, P1
32-bit primary PCI slot 2, P2
32-bit secondary PCI slot 3, P3
32-bit secondary PCI slot 4, P4
32-bit secondary PCI slot 5, P5
32-bit secondary PCI slot 6, P6
64-bit PCI slot 7, P7
64-bit PCI slot 8, P8
64-bit PCI slot 9, P9
64-bit PCI slot 10, P10
CPU baseboard with four 65 W
processors 4.6 A 6.2 A 28.5 A
Primary memory module (16 256MB
DIMMs) 13.6 A
Secondary memory module (16
256MB DIMMs) 13.6 A
3.5-inch diskette drive 0.65 A
CD-ROM drive 0.55 A 0.60 A
1st SCA hard disk drive
2nd SCA hard disk drive
continued