IBM System x3620 M3 7376 Installation And User Manual page 77

v When you install or remove DIMMs, the server configuration information
changes. When you restart the server, the system displays a message that
indicates 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 (single-rank or dual-rank), synchronous
dynamic random-access memory (SDRAM) dual inline memory modules (DIMMs)
with error correcting code (ECC). See http://www.ibm.com/servers/eserver/
serverproven/compat/us/ for a list of supported memory modules for the server.
v The specifications of a DDR3 DIMM are on a label on the DIMM, in the following
format.
ggg eRxff-PC3-wwwwwm-aa-bb-cc
where:
ggg is the total capacity of the DIMM (for example, 1GB, 2GB, or 4GB)
e is the number of ranks
1 = single-rank
2 = dual-rank
4 = quad-rank
ff is the device organization (bit width)
4 = x4 organization (4 DQ lines per SDRAM)
8 = x8 organization
16 = x16 organization
wwwww is the DIMM bandwidth, in MBps
6400 = 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 type
E = 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 frequency
bb is the JEDEC SPD Revision Encoding and Additions level
cc is the reference design file for the design of the DIMM
v The following rules apply to single-rank and dual-rank DDR3 DIMM speed as it
relates to the number of DIMMs in a channel:
– When you install 1 DIMM per channel, the memory runs at 1333 MHz
– When you install 2 DIMMs per channel, the memory runs at 1066 MHz
– All channels in a server run at the fastest common frequency
v The maximum memory speed is determined by the combination of the
microprocessor, DIMM speed, and the number of DIMMs installed in each
channel.
v In two-DIMM-per-channel configuration, a server with an Intel Xeon X5600 series
microprocessor automatically operates with a maximum memory speed of up to
1333 MHz when one of the following conditions is met:
– Two 1.5 V single-rank or dual-rank RDIMMs are installed in the same channel.
In the Setup utility, Memory speed is set to Max performance mode
Chapter 2. Installing optional devices
61