IBM System x3650 M3 4255 Installation And User Manual page 121

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
d is the revision number of the reference design of the DIMM
v The following rules apply to 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
– When you install 3 DIMMs per channel, the memory runs at 800 MHz
– All channels in a server run at the fastest common frequency.
– Do not install registered and unbuffered DIMMs in the same server.
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
– Two 1.35 V single-rank or dual-ranl RDIMMs are installed in the same
channel. In the Setup utility, Memory speed is set to Max performance and
LV-DIMM power is set to Enhance performance mode. The 1.35 V RDIMMs
will function at 1.5 V
v The server supports a maximum of 18 single-rank or dual-rank RDIMMs. The
server supports up to 12 single-rank or dual-rank UDIMMs or quad-rank
RDIMMs.
Note: To determine the type of a DIMM, see the label on the DIMM. The
information on the label is in the format xxxxx nRxxx PC3-xxxxx-xx-xx-xxx. The
numeral in the sixth numerical position indicates whether the DIMM is single-rank
(n=1), dual-rank (n=2), or quad-rank (n=4).
v The server supports three single-rank or dual-rank DIMMs per channel. The
server supports a maximum of two quad-rank RDIMMs per channel. The
following table shows an example of the maximum amount of memory that you
can install using ranked DIMMs:
Chapter 2. Installing optional devices
105