Lenovo Flex System x240 M5 Product Manual page 13

All DIMMs in all CPU memory channels operate at the same speed, which is determined as the

lowest value of the following factors:
Memory speed that is supported by the specific CPU.

Lowest maximum operating speed for the selected memory configuration that depends on rated

speed, as shown in the "Maximum operating speed" section in the following table.
The following table shows the maximum memory speeds that are achievable based on the installed
DIMMs and the number of DIMMs per channel. The table also shows the maximum memory capacity at
any speed that is supported by the DIMM and maximum memory capacity at rated DIMM speed. In the
table, cells that are highlighted in gray indicate when the specific combination of DIMM voltage and
number of DIMMs per channel still allows the DIMMs to operate at the rated speed.
Table 8. Maximum memory speeds
Specification
Rank
Part numbers
Rated speed
Rated voltage
Operating voltage
Maximum quantity*
Largest DIMM
Max memory capacity
Max memory at rated
speed
Maximum operating speed (MHz)
One DIMM per channel
Two DIMMs per channel
Three DIMMs per channel
* The maximum quantity that is supported is shown for two processors that are installed. When one processor is
installed, the maximum quantity that is supported is half of that shown.
† This speed is achieved only when Lenovo TruDDR4 memory is used
The following memory protection technologies are supported:
ECC

Memory mirroring

Memory sparing

If memory mirroring is used, DIMMs must be installed in pairs (minimum of one pair per CPU), and both
DIMMs in a pair must be identical in type and size.
If memory rank sparing is used, a minimum of one quad-rank DIMM or two single-rank or dual-rank
DIMMs must be installed per populated channel (the DIMMs do not need to be identical). In rank sparing
mode, one rank of a DIMM in each populated channel is reserved as spare memory. The size of a rank
varies depending on the DIMMs that are installed.
Lenovo Flex System x240 M5
RDIMMs
Single rank
46W0784 (4 GB)
46W0788 (8 GB)
2133 MHz
1.2 V
1.2 V
24
8 GB
192 GB
128 GB
2133 MHz
2133 MHz
1600 MHz
Dual rank
46W0792 (8 GB)
95Y4821 (16 GB)
95Y4808 (32 GB)
2133 MHz
1.2 V
1.2 V
24
16 GB
384 GB
256 GB
2133 MHz
2133 MHz†
1600 MHz
LRDIMMs
Quad rank
46W0800 (32 GB)
95Y4812 (64 GB)
2133 MHz
1.2 V
1.2 V
24
64 GB
1.5 TB
1.0 TB
2133 MHz
2133 MHz†
1866 MHz†
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