User`s guide

Upgrading Your Server 9-27
Memory Clock
Memory clock speed depends on CPU model and whether the additional 8-GB memory board is installed or not.
 Xeon E5502/E5504
Always operates at 800MHz regardless of DIMM type.
 Xeon E5520/X5550/X5570
Operates at 800MHz when the following conditions are satisfied. In other cases, operates at 1066MHz. The memory
clock is stationary for each CPU.
<Condition>
An additional 8-GB memory board is installed and each CPU has four or more DIMMs installed.
<Example>
Operates at 800MHz Operates at 1066MHz
Memory RAS Feature
The server supports memory mirroring and LockStep (x8 SDDC) features as memory RAS feature. They are optional. Contact
your service representative for details. For configuration, see "Using the Memory RAS Features" described later.
To use x4 SDDC feature, you need to remove the factory-installed DIMMs and install 2GB/4GB/8GB DIMMs.