Intel SE7520JR2SCSID2 User Guide - Page 22

Server Board Features DIMMs must meet the following requirements: ƒ Use only DDR266. DDR333, or DDR2-400 ECC, registered DDR DIMM modules (DDR-2 400 on SE7520JR2SCSID2 and SE7520JR2SATAD2 only) ƒ Use only DIMMs that comply with the DDR specifications. ƒ DDR266 and DDR333 memory can be mixed on the server board, but when mixing DIMM types, DDR333 memory will be treated as DDR266. ƒ Use only DIMMs with DIMM organization of x72 ECC ƒ Use only 184-pin DIMMs on boards that use DDR266/333 ƒ Use only 240pin DIMMs on boards that use DDR2-400 ƒ Use only DIMMs with the capacities outlined in the following table can be used Table 5. DIMM Module Memory Capacity Support SDRAM Parts, SDRAM Technology X8, single row X8, double row X4, single row X4, stacked, double row 128MB 128MB 256MB 256MB 512MB 256MB 256MB 512MB 512MB 1GB 512MB 512MB 1GB 1GB 2GB 1GB 1GB 2GB 2GB 4GB ✏ NOTE When using either Dual Rank (Double Row) DDR-333 or 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 technoloiges, 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. In determining your memory requirements, the need for memory sparing or memory mirroring must be considered. For a complete list of supported memory DIMMs, see the links under "Additional Information and Software." 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 a DIMM fails. With memory mirroring the system maintains two copies of all data in the memory subsystem. 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. 22