Hardware options installation 44
• Populate DIMM slots for a processor only if the processor is installed.
• To maximize performance in multi-processor configurations, distribute the total memory capacity
between all processors as evenly as possible.
• Do not mix Unbuffered and Registered PC3 DIMMs.
• Each channel supports up to two Unbuffered DIMMs.
• If quad-rank DIMMs are installed for a processor, a maximum of two DIMMs can be installed on each
channel for that processor.
• If a channel contains quad-rank DIMMs, the quad-rank DIMM must be installed first on that channel.
DIMM speeds are supported as indicated in the following table.
Populated slots
(per channel)
Rank Speeds supported
(MHz)
1
Single- or dual-rank 1333, 1066
1
Quad-rank 1066
2
Single- or dual-rank 1066
3
Single- or dual-rank 800
Advanced ECC population guidelines
For Advanced ECC mode configurations, observe the following guidelines:
• Observe the general DIMM slot population guidelines (on page 43).
• DIMMs may be installed individually.
Single-processor Advanced ECC population order
For Advanced ECC mode configurations with a single processor, populate the DIMM slots in the following
order:
• RDIMM: Sequentially in alphabetical order (A through I)
• UDIMM: A through F, sequentially in alphabetical order. Do not populate DIMM slots G through I.
Multi-processor Advanced ECC population order
For Advanced ECC mode configurations with multiple processors, populate the DIMM slots for each
processor in the following order:
• RDIMM: Sequentially in alphabetical order (A through I)
• UDIMM: A through F, sequentially in alphabetical order. Do not populate DIMM slots G through I.
Lockstep Memory population guidelines
For Lockstep memory mode configurations, observe the following guidelines:
• Observe the general DIMM slot population guidelines (on page 43).
• Always install DIMMs in channels 1 and 2 for each installed processor.
• Do not install DIMMs in channel 3 for any processor.
• DIMM configuration on channel 1 and channel 2 of a processor must be identical.
