Lenovo ThinkSystem ST650 V2 - Page 74

Table 24. Independent mode with two processors and different capacity memory modules (processor 2)
Total
DIMMs
Processor 2
Total
DIMMs
17 18 19 20 21 22 23 24
25 26 27 28 29 30 31 32
4 19 21 4
8 19 21 28 30 8
16
1,2
17 19 21 23 26 28 30 32 16
1,2
24
1,2
17 19 20 21 23 24 25 26 28 29 30 32 24
1,2
32
1,2
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 32
1,2
Notes:
1. DIMM configurations that support Sub NUMA Clustering (SNC), which can be enabled via UEFI.
2. DIMM configurations that support Software Guard Extensions (SGX), see “Enable Software Guard
Extensions (SGX)” on page 157 to enable this feature.
Memory mirroring mode
Memory-mirroring mode provides full memory redundancy while reducing the total system memory capacity
in half. Memory channels are grouped in pairs with each channel receiving the same data. If a failure occurs,
the memory controller switches from the DIMMs on the primary channel to the DIMMs on the backup
channel. The DIMM installation order for memory mirroring varies based on the number of processors and
DIMMs installed in the server.
Attention: Memory mirroring guidelines:
• Mirroring can be configured across two channels.
• Both channels must be populated in each iMC.
• The total memory size of the primary and secondary channels must be the same.
• Memory mirroring is supported when PMEMs are installed and set to 100% App Direct Mode.
• Memory mirroring mode is limited to DDR4 memory modules only, PMEM memory mirroring is not
supported in App Direct Mode.
Channels Channel 0 Channel 1
Slots Slot 1 Slot 0 Slot 1 Slot 0
Identical DIMM installation required
Y Y
Identical DIMM installation required for
full channel mirroring
Y Y Y Y
Note: When adding one or more DIMMs during a memory upgrade, you might need to remove some DIMMs
that are already installed to new locations.
Mirror memory mode with one processor
Table 25. Mirror mode with one processor
Total
DIMMs
Processor 1
Total
DIMMs
1 2 3 4
5 6 7 8 9 10 11 12 13 14 15 16
8* 1 3 5 7 10 12 14 16 8*
16* 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 16*
66 ThinkSystem ST650 V2 Setup Guide