Table 4. Dimm Module Memory Capacity Support - Intel SSR212CC User Manual

Hardware Installations and Upgrades
•
DDR2-400 ECC, registered DDR DIMM modules
•
Use only DIMMs that comply with the DDR specifications
•
Use only DIMMs with a DIMM organization of x72 ECC
•
Use only 240-pin DIMMs
•
Use only DIMMs with the capacities outlined in the following table.

Table 4. DIMM Module Memory Capacity Support

Note: When using either dual-rank (double-row) DDR2-400 DIMM technologies, a maximum of
four loads per memory channel is supported. When all DIMMs used in the system match
either of these technologies, a maximum of four DIMMs can be populated. Refer to the
Intel® Server Board SE7520JR2 Technical Product Specification for additional
information regarding the memory sub-system.
Memory Sparing and Mirroring
The Intel® E7520 chipset includes hardware that supports memory mirroring and memory
on-line sparing. Both memory mirroring and memory on-line sparing provide a way to
prevent data loss in case of a DIMM failure.
With memory mirroring, the system maintains two copies of all data in the memory sub-
system. If a DIMM fails, the data is not lost because the second copy of the data is
available from the mirrored DIMM in the opposite channel. The system will not fail due
to memory error unless both the primary and the mirrored copy of the data become corrupt
at the same time.
In a mirrored system, the maximum usable memory is one-half of the installed memory,
with a minimum of four DIMMs installed. Since the data is duplicated across DIMMs, it
means that up to one-half of the installed DIMMs are actively in use at any one time. The
remaining DIMMs are used for mirroring.
Two methods for memory mirroring are available:
•
Four identical DIMMs are used in DIMM sockets 1A, 1B, 2A, and 2B
— If the DIMM in socket 1A fails, the DIMM in socket 2B takes over.
— If the DIMM in socket 1B fails, the DIMM in socket 2A takes over.
•
Four DIMMs are used with identical single-ranked DIMMs in banks 2 and 3. DIMMs
in sockets 1A and 1B must be dual-ranked and identical.
90
SDRAM Parts, SDRAM
Technology
x8, single row
x8, double row
x4, single row
x4, stacked, double row
256 MB 512 MB
256 MB 512 MB
512 MB 1 GB
512 MB 1 GB
1 GB 2 GB
Intel® Storage System SSR212CC User Guide
1 GB
1 GB
2 GB
2 GB
4 GB