Oracle X7-8 Service Manual page 187

When installing DIMMs, consider the following rules:
When two DIMMs are in a channel, the channel speed defaults to the maximum supported
■
speed (listed in the DIMM's SPD and read by BIOS) of the slowest DIMM in the channel.
For example: if an 1866 MT/s-compliant DIMM is installed in a channel with a 2133 MT/s -
compliant DIMM, the channel speed is limited to 1866 MT/s.
A maximum of 8 logical ranks (ranks seen by the host) per channel is allowed.
■
When one DIMM is used, it must be populated in DIMM slot 0 (farthest away from the
■
CPU) of a given channel.
When single-rank or dual-rank RDIMMs are populated for 2DPC (two DIMMs per
■
channel), always populate the higher quantity rank DIMM first (starting from the farthest
slot). For a 2SPC (two slots per channel) example, first populate a dual-rank DIMM in the
DIMM0 slot. Then a single-rank DIMM may be populated in the DIMM1 slot.
All CMODs should be populated identically.
■
Memory quantity needs to be equal across all CMODs.
■
All DIMMs in a system should be the same type and size.
■
The minimum DIMM configuration as shipped from the factory is four 16-GB DIMMs in
■
each CMOD, installed is slots D0, D6, D12 and D18.
An upgrade of four DIMMs for each CMOD is allowed in this configuration by installing
four DIMMs in slots D3, D9, D15 and D21.
Aside from an upgrade to the minimum shipped configuration (stated above), DIMMs must
■
be added to each CMOD in sets of eight (one for each memory buffer channel). Add eight
DIMMs to each CMOD starting with CMOD0 and ending with CMOD3 (four-CMOD
configuration) or CMOD7 (eight-CMOD configuration). After all CMODs are populated,
go back to CMOD0 and repeat the sequence adding the next set of eight DIMMs to each
CMOD.
For example: CMOD0 gets the initial eight DIMMs, followed by CMOD1 with the next
eight DIMMs, continuing with all CMODs in the configuration. When 32 DIMMs (4-
CMOD) or 64 DIMMs (8-CMOD) have been added across all CMODs in the configuration,
go back to CMOD0 for the next set of eight DIMMs and continue this population pattern.
Each CMOD must only contain one size of DIMM. Mixing of different size memory within
■
a CMOD is not allowed. Size mixing between CMODs is not allowed.
Mixing of LVDIMM and LRDIMM in the same chassis is not allowed.
■
DIMM Population Scenarios
There are three scenarios in which you are required to populate DIMMs:
A DIMM fails and needs to be replaced.
■
Install a Processor
Servicing Components 187