IBM System x3400 M3 Types 7378 Installation And User Manual page 97

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
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 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
Note: The server does not support quad-rank RDIMM.
The server supports a maximum of 16 single-rank or dual-rank RDIMMs. The
server supports up to 12 single-rank or dual-rank UDIMMs.
v The server supports three single-rank or dual-rank DIMMs per channel on
channel 0 and 1, two single-rank or dual-rank DIMMs on channel 2. The following
table shows an example of the maximum amount of memory that you can install
using ranked DIMMs:
Table 6. Maximum memory installation using ranked DIMMs
Number of DIMMs DIMM type
12 Single-rank UDIMMs
12 Dual-rank UDIMMs
16 Single-rank RDIMMs
16 Dual-rank RDIMMs
DIMM size Total memory
2 GB 24 GB
4 GB 48 GB
2 GB 32 GB
2 GB 32 GB
Chapter 2. Installing optional devices
81