Lenovo Flex System x240 M5
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
RDIMMs
LRDIMMs
Rank
Single rank
Dual rank
Quad rank
Part numbers
46W0784 (4 GB)
46W0788 (8 GB)
46W0792 (8 GB)
95Y4821 (16 GB)
95Y4808 (32 GB)
46W0800 (32 GB)
95Y4812 (64 GB)
Rated speed
2133 MHz
2133 MHz
2133 MHz
Rated voltage
1.2 V
1.2 V
1.2 V
Operating voltage
1.2 V
1.2 V
1.2 V
Maximum quantity*
24
24
24
Largest DIMM
8 GB
16 GB
64 GB
Max memory capacity
192 GB
384 GB
1.5 TB
Max memory at rated
speed
128 GB
256 GB
1.0 TB
Maximum operating speed (MHz)
One DIMM per channel
2133 MHz
2133 MHz
2133 MHz
Two DIMMs per channel
2133 MHz
2133 MHz†
2133 MHz†
Three DIMMs per channel
1600 MHz
1600 MHz
1866 MHz†
* 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.
