Technical Reference
59
2.10
Electrical Considerations
2.10.1
DC Loading
Table 28 lists the DC loading characteristics of the boards. This data is based on a DC
analysis of all active components within the board that impact its power delivery
subsystems. The analysis does not include PCI add-in cards. Minimum values assume
a light load placed on the board that is similar to an environment with no applications
running and no USB current draw. Maximum values assume a load placed on the
board that is similar to a heavy gaming environment with a 500 mA current draw per
USB port. These calculations are not based on specific processor values or memory
configurations but are based on the minimum and maximum current draw possible
from the board’s power delivery subsystems to the processor, memory, and USB
ports.
Use the datasheets for add-in cards, such as PCI, to determine the overall system
power requirements. The selection of a power supply at the system level is dependent
on the system’s usage model and not necessarily tied to a particular processor speed.
Table 28. DC Loading Characteristics
DC Current at:
Mode
DC Power
+3.3 V
+5 V
+12 V
-12 V
+5 VSB
Minimum loading
275 W
3.5 A
12 A
17 A
0 A
0.34 A (S0)
1.00 A (S3)
Maximum loading
500 W
16 A
23 A
29 A
0.20 A
0.34 A (S0)
1.10 A (S3)
2.10.2
Add-in Board Considerations
The boards are designed to provide 2 A (average) of +5 V current for each add-in
board. The total +5 V current draw for both boards is as follows: a fully loaded
D945GCL board (all three expansion slots and the PCI Express x16 slot filled) must not
exceed 8 A.
