Dell 7910 owner manual Power supply units, Hot Spare feature

NOTE: Tighten the screws diagonally opposite to each other. Do not over-tighten the heat sink retention screws when installing the heat sink. To prevent over-tightening, tighten the retention screw until resistance is felt, and stop once the screw is seated. The screw tension should be no more than 6 in-lb (6.9 kg-cm).

1.Install the cooling shroud.

2.If applicable, install the PCIe card.

3.If applicable, install the cooling fan assembly.

4.Follow the procedure listed in After working inside your system.

5.While booting, press <F2> to enter the System Setup and check that the processor information matches the new system configuration.

6.Run the system diagnostics to verify that the new processor operates correctly.

Power supply units

Your system supports:

•Two 1100 W AC power supply modules

NOTE: Titanium power supply unit is nominally rated for 200 VAC to 240 VAC input only.

NOTE: When two identical PSUs are installed, power supply redundancy (1+1 – with redundancy or 2+0 – without redundancy) is configured in system BIOS. In redundant mode, power is supplied to the system equally from both PSUs when Hot Spare is disabled. When Hot Spare is enabled, one of the PSUs will be put into standby when system utilization is low in order to maximize efficiency.

NOTE: For AC power supply units, use only power supply units with the Extended Power Performance (EPP) label on the back. Mixing power supply units from previous generations of servers can result in a power supply unit mismatch condition or failure to power on.

Hot Spare feature

Your system supports the Hot Spare feature that significantly reduces the power overhead associated with power supply redundancy.

When the Hot Spare feature is enabled, one of the redundant PSUs is switched to the sleep state. The active PSU supports 100% of the load, thus operating at higher efficiency. The PSU in the sleep state monitors output voltage of the active PSU. If the output voltage of the active PSU drops, the PSU in the sleep state returns to an active output state.

If having both PSUs active is more efficient than having one PSU in a sleep state, the active PSU can also activate a sleeping PSU.

The default PSU settings are as follows:

•If the load on the active PSU is more than 50%, then the redundant PSU is switched to the active state.

•If the load on the active PSU falls below 20%, then the redundant PSU is switched to the sleep state.

You can configure the Hot Spare feature by using the iDRAC settings. For more information on iDRAC settings, see the Integrated Dell Remote Access Controller User’s Guide at dell.com/support/home.

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