Installing a memory moduleThe following notes describe the types of dual inline memory modules (DIMMs) thatthe server supports and other information that you must consider when you installDIMMs:v To confirm that the server supports the DIMM that you are installing, seehttp://www.ibm.com/systems/info/x86servers/serverproven/compat/us/.v When you install or remove DIMMs, the server configuration informationchanges. When you restart the server, the system displays a message thatindicates that the memory configuration has changed.v The server supports only industry-standard double-data-rate 3 (DDR3), 800,1066, or 1333 MHz, PC3-10600R-999, synchronous dynamic random-accessmemory (SDRAM) registered dual inline memory modules (DIMMs) with errorcorrecting code (ECC).v The specifications of a DDR3 DIMM are on a label on the DIMM, in the followingformat.ggg eRxff-PC3-wwwwwm-aa-bb-ccwhere:ggg is the total capacity of the DIMM (for example, 1GB, 2GB, or 4GB)e is the number of ranks1 = single-rank2 = dual-rank4 = quad-rankff is the device organization (bit width)4 = x4 organization (4 DQ lines per SDRAM)8 = x8 organization16 = x16 organizationwwwww is the DIMM bandwidth, in MBps6400 = 6.40 GBps (PC3-800 SDRAMs, 8-byte primary data bus)8500 = 8.53 GBps (PC3-1066 SDRAMs, 8-byte primary data bus)10600 = 10.66 GBps (PC3-1333 SDRAMs, 8-byte primary data bus)12800 = 12.80 GBps PC3-1600 SDRAMs, 8-byte primary data bus)m is the DIMM typeE = Unbuffered DIMM (UDIMM) with ECC (x72-bit module data bus)R = Registered DIMM (RDIMM)U = Unbuffered DIMM with no ECC (x64-bit primary data bus)aa is the CAS latency, in clocks at maximum operating frequencybb is the JEDEC SPD Revision Encoding and Additions levelcc is the reference design file for the design of the DIMMv The maximum memory speed is determined by the combination of themicroprocessor, DIMM speed, and the number of DIMMs installed in eachchannel.v The following rules apply to DDR3 DIMM speed as it relates to the number ofDIMMs in a channel:– When you install one DIMM single-rank or dual-rank per channel, the memoryruns at 1333 MHz– When you install two DIMMs single-rank or dual-rank per channel, thememory runs at 1066 MHz162 IBM System x3630 M3 Type 7377: Problem Determination and Service Guide
