Memory Options - IBM System x3950 X6 Product Manual

Memory options

IBM DDR3 memory is compatibility tested and tuned for optimal IBM System x® performance and
throughput. IBM memory specifications are integrated into the light path diagnostics for immediate system
performance feedback and optimum system uptime. From a service and support standpoint, IBM memory
automatically assumes the IBM system warranty, and IBM provides service and support worldwide.
The x3950 X6 supports DDR3 memory operating at speeds up to 1600 MHz. The server supports up to
192 DIMMs when all eight processors are installed, 24 DIMMs per processor. Each processor has four
memory channels that are implemented using Scalable Memory Interface generation 2 (SMI2) chips, and
the server implements three DIMMs per channel. The processor and the corresponding memory DIMM
slots are on the Compute Book.
The following table lists the memory options that are available for x3950 X6.
Table 4. Memory options
Part Feature
number code
RDIMMs
00D5024 A3QE
00D5036 A3QH
46W0672 A3QM
LRDIMMs
46W0676 A3SR
46W0741 A451
The following rules apply when selecting the memory configuration:
The server supports RDIMMs and LRDIMMs.

Mixing different types of memory (RDIMMs and LRDIMMs) is not supported.

The maximum number of ranks per one DDR3 channel is six with RDIMMs or 24 with LRDIMMs.

In RAS (lockstep) mode, DIMMs must be installed in a pair.

The maximum quantity of DIMMs that can be installed in the server depends on the number of

processors, DIMM type, rank, and operating voltage, as shown in the "Max. qty supported" row in the
following table.
All DIMMs in the server operate at the same speed, which is determined as the lowest value of one of

the following options:
o
Memory speed that is supported by the specific processor.
o Lowest of maximum operating speeds for selected memory configuration that depends on rated
speed, operating voltage, and quantity of DIMMs per channel, as shown under "Maximum
operating speed" section in the following table.
IBM System x3950 X6
Description
4GB (1x4GB, 1Rx4, 1.35V) PC3L-12800 CL11 ECC
DDR3 1600MHz LP RDIMM
8GB (1x8GB, 1Rx4, 1.35V) PC3L-12800 CL11 ECC
DDR3 1600MHz LP RDIMM
16GB (1x16GB, 2Rx4, 1.35V) PC3L-12800 CL11
ECC DDR3 1600MHz LP RDIMM
32GB (1x32GB, 4Rx4, 1.35V) PC3L-12800 CL11
ECC DDR3 1600MHz LP LRDIMM
64GB (1x64GB, 8Rx4, 1.35V) PC3-10600 DDR3
1333MHz LP LRDIMM
Maximum Standard
supported models
x3950 X6 where used
192 (24 per -
CPU)
192 (24 per BAx, CAx, CCx
CPU)
192 (24 per -
CPU)
192 (24 per -
CPU)
192 (24 per -
CPU)
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