Unbuffered Dimms (Udimms) - Lenovo ThinkServer TS200 Installation And User Manual

The following sections provide additional information specific to unbuffered and
registered DIMMs that you must consider.

Unbuffered DIMMs (UDIMMs)

The following notes provide information that you must configure when you install
UDIMMs:
v The memory channels run at the fastest common frequency of the installed
v Do not use both UDIMMs and RDIMMs in the same server.
v Using ECC and non-ECC UDIMMs in the server will cause the server to run in
v The UDIMM options that are available for the server are 1 GB, 2 GB, and 4 GB
v You can install a maximum of 16 GB of memory in some server models when
v The server supports up to two single-rank or dual-rank UDIMMs per channel.
v DIMM slots 3 and 6 are not supported when you install UDIMMs in the server.
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
8500 = 8.53 GBps (PC3-1066 SDRAMs, 8-byte primary data bus)
10600 = 10.66 GBps (PC3-1333 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) or dual-rank (n=2).
DIMMs.
non-ECC mode.
(when available) memory DIMMs.
you use UDIMMs.
Do not install DIMMs in these connectors.
Chapter 5. Installing and replacing optional devices
39