Dell PowerEdge VRTX - Manual (Page 33)

• Up to three LRDIMMs can be populated regardless of rank count.
• Up to two quad-rank RDIMMs and up to three dual- or single-rank RDIMMs can be populated per channel.
When a quad-rank RDIMM is populated in the first slot with white release levers, the third DIMM slot in the
channel with green release levers cannot be populated.
• Populate DIMM sockets only if a processor is installed. For single-processor systems, sockets A1 to A12 are
available. For dual-processor systems, sockets A1 to A12 and sockets B1 to B12 are available.
• Populate all sockets with white release tabs first, then black, and then green.
• Do not populate the third DIMM socket in a channel with green release tabs, if a quad-rank RDIMM is populated
in the first socket with white release tabs.
• Populate the sockets by highest rank count in the following order - first in sockets with white release levers,
then black, and then green. 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.
• 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, 2 GB and 4 GB memory modules can be mixed).
• Populate four DIMMs per processor (one DIMM per channel) at a time to maximize performance.
• 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.
• Populate DIMMs based on the following processor— heat sink configurations.
Table 1. Processor—Heat Sink Configuration
Processor
Configuration
Processor
Type (in
Watts)
Heat Sink Number of DIMMs
Maximum System Capacity Reliability, Availability, and
Serviceability (RAS) Features
Single processor up to 95 W 57 mm 12 12
Single processor 115 W or
130 W
77 mm 10 (Three DIMMs in
channels 0 and 3 and two
DIMMs in channels 1 and 2)
8 (Two DIMMs per channel)
Dual processor up to 95 W 57 mm 24 24
Dual processor 115 W or
130 W
77 mm 20 (Three DIMMs in
channels 0 and 3 and two
DIMMs in channels 1 and 2)
16 (Two DIMMs per channel)
NOTE: For optimal performance, your system may be configured with a larger heat sink than listed above.
Do not use any heat sink smaller than the configurations described above.
Mode-Specific Guidelines
Four memory channels are allocated to each processor. 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
memory optimized (independent channel) mode. x8 DRAM based DIMMs require Advanced ECC mode to gain
SDDC.
The following sections provide additional slot population guidelines for each mode.
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