Memory Dimm Rules - Silicon Graphics Altix XE250 User Manual

Memory DIMM Rules

007-5467-001
Use the following rules when installing memory DIMMs:
• A minimum of two DIMMs must always be present.
• DIMMs within pairs must be identical in:
• Size (1, 2, or 4 GB)
• Speed (667 or 800 Mtransfer/sec)
• Organization (x4 or x8 bit)
• DIMMs do not need to be identical between DIMM pairs. DIMM pair 1A/2A can be
different from DIMM pair 3A/4A in size, speed and organization.
Note: The memory controller hub automatically adjusts to the lowest speed DIMM of the DIMM
pair.
• When configuring the memory for maximum performance, it is critical that the memory
DIMM capacity is balanced across both memory branches (refer to
The MCH memory controller has two memory branches: Branch 0 and Branch 1. DIMMs 1A, 2A,
1B, and 2B are on branch 0 and DIMMs 3A, 4A, 3B, and 4B are on branch 1. If the total capacity
of the memory DIMMs on each branch are not balanced, memory performance is degraded.
• Install DIMMs with the same capacity in the following order:
• 2 DIMMs - Install DIMM pair 1
• 4 DIMMs - Install DIMM pair 1 and 2
• 8 DIMMs - Install DIMM pair 1, 2, 3, and 4
• 12 DIMMs - Install DIMM pairs 1, 2, 3, 4, 5, and 6
• 16 DIMMs - All DIMM slots filled
Install Memory
Figure 3-9).
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