DIMM Type DIMMs
Populated/
Channel
Operating Frequency (in MT/s)
Maximum DIMM Rank/
Channel
1.5 V
1.35 V
2
1600, 1333, 1066, and 800
1066 and 800
1333, 1066, and 800
1066 and 800
Dual rank
Quad rank
General Memory Module Installation Guidelines
NOTE: Memory configurations that fail to observe these guidelines can prevent your system from booting, hanging
during memory configuration, or operating with reduced memory.
This system supports Flexible Memory Configuration, enabling the system to be configured and run in any valid chipset
architectural configuration. The following are the recommended guidelines for best performance:
•
UDIMMs and RDIMMs must not be mixed.
•
x4 and x8 DRAM based DIMMs can be mixed. For more information, see Mode-Specific Guidelines.
•
A maximum of two UDIMMs can be populated in a channel.
•
A maximum of two single- or dual-rank RDIMMs can be populated in a channel.
•
Populate all sockets with white release tabs first, and then black.
•
Populate the sockets by highest rank count in the following order - first in sockets with white release levers, and
then black. For example, if you want to mix quad-rank and dual-rank DIMMs, populate quad-rank DIMMs in the
sockets with white release tabs and dual-rank DIMMs in the sockets with black release tabs.
•
Memory modules of different sizes can be mixed provided that other memory population rules are followed (for
example, 2 GB and 4 GB memory modules can be mixed).
•
Depending on mode-specific guidelines, populate two or three DIMMs per processor (one DIMM per channel)
at a time to maximize performance. For more information, see Mode-Specific Guidelines.
•
If memory modules with different speeds are installed, they will operate at the speed of the slowest installed
memory module(s) or slower depending on system DIMM configuration.
Mode-Specific Guidelines
The allowable configurations depend on the memory mode selected.
NOTE: x4 and x8 DRAM based DIMMs can be mixed providing support for RAS features. However, all guidelines for
specific RAS features must be followed. x4 DRAM based DIMMs retain Single Device Data Correction (SDDC) in
either memory optimized (independent channel) or Advanced ECC modes. x8 DRAM based DIMMs require
Advanced ECC mode to gain SDDC.
The following sections provide additional slot population guidelines for each mode.
Advanced ECC (Lockstep)
Advanced ECC mode extends SDDC from x4 DRAM based DIMMs to both x4 and x8 DRAMs. This protects against single
DRAM chip failures during normal operation.
Memory sockets A1 and A4 are disabled and you can populate DIMMs in memory sockets A2, A3, A5, and A6.
NOTE: Advanced ECC with Mirroring is not supported.
Memory Optimized (Independent Channel) Mode
This mode supports SDDC only for memory modules that use x4 device width and does not impose any specific slot
population requirements.
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