Owners Manual

• Populate the sockets by highest capacity DIMM in the following order - first in sockets with white
release levers and then black. For example, if you want to mix 16 GB and 8 GB DIMMs, populate 16 GB
DIMMs in the sockets with white release tabs and 8 GB DIMMs in the sockets with black release tabs.
• In a dual-processor configuration, the memory configuration for each processor must be identical.
For example, if you populate socket A1 for processor 1, then populate socket B1 for processor 2, and
so on.
• Memory modules of different sizes can be mixed provided that other memory population rules are
followed (for example, 4 GB and 8 GB memory modules can be mixed).
• Depending on mode-specific guidelines, populate four DIMMs per processor (one DIMM per channel)
at a time to maximize performance. For more information, see the Mode-specific guidelines section.
Table 21. Heat sink — processor configurations
Processor
Configuration
Processor Type (in
Watts)
Heat
Sink
Width
Number of DIMMs
Maximum System
Capacity
Reliability, Availability,
and Serviceability (RAS)
Features
Dual processor Up to 135 W 74
mm
24 24
Quad processor Up to 105 W 74
mm
48 48
120 W or 135 W 94
mm
40 (Three DIMMs in
channel 0 and channel
2 and two DIMMs in
channel 1 and channel
3)
32 (Two DIMMs per
channel)
Related Links
Mode-specific guidelines
Mode-specific guidelines
Four memory channels are allocated to each processor. The allowable configurations depend on the
memory mode selected.
Advanced Error Correction Code (lockstep)
Advanced Error Correction Code (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.
The installation guidelines for memory modules are as follows:
• Memory modules must be identical in size, speed, and technology.
• DIMMs installed in memory sockets with white release levers must be identical and the same rule
applies for sockets with black release levers. This ensures that identical DIMMs are installed in
matched pair —for example, A1 with A2, A3 with A4, A5 with A6, and so on.
Memory optimized (independent channel) mode
This mode supports Single Device Data Correction (SDDC) only for memory modules that use x4 device
width. It does not impose any specific slot population requirements.
71