Unbuffered Dimms (Udimms) - Lenovo ThinkServer TS200 Hardware Maintenance Manual

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).
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:
• The memory channels run at the fastest common frequency of the installed DIMMs.
• Do not use both UDIMMs and RDIMMs in the same server.
• Using ECC and non-ECC UDIMMs in the server will cause the server to run in non-ECC mode.
• The UDIMM options that are available for the server are 1 GB, 2 GB, and 4 GB (when available) memory
DIMMs.
• You can install a maximum of 16 GB of memory in some server models when you use UDIMMs.
• The server supports up to two single-rank or dual-rank UDIMMs per channel.
• DIMM slots 3 and 6 are not supported when you install UDIMMs in the server. Do not install DIMMs in
these connectors.
• The following table lists the supported UDIMM population.
Table 8. Supported UDIMM population per channel
DIMMs slots per
channel
2
2
• The following table lists the maximum DIMM population using ranked UDIMM.
Table 9. Maximum memory population using ranked UDIMMs (depending on your model)
Number of UDIMMs
4
4
4
4
• The following table lists the UDIMM memory population rule to optimize the system performance.
148
Hardware Maintenance Manual
DIMMs installed in
each channel DIMM type
1 Unbuffered DDR3
ECC
2
Unbuffered DDR3
ECC
DIMM type
single-rank UDIMMs
single-rank UDIMMs
dual-rank UDIMMs
dual-rank UDIMMs
DIMM speed
1066, 1333
1066, 1333
DIMM size
1 GB
2 GB
2 GB
4 GB (when available)
Ranks per DIMM
(any combination)
single-rank,
dual-rank
single-rank,
dual-rank
Total memory
4 GB
8 GB
8 GB
16 GB