Dell 1950 General Memory Module Installation Guidelines, Non-Optimal Memory Configurations, Memory Sparing Support

64 Installing System Components
Each channel consists of two memo ry module sockets:
• Channel 0 contains DIMM_1, DIMM_5.
• Channel 1 contains DIMM _2, DIMM_6.
• Channel 2 contains DIMM_3, DIMM_7.
• Channel 3 contains DIMM _4, DIMM _8.
The first DIMM socket of each channel has white release tabs.
General Memory Module Installation Guidelines
To ensure optimal performance of your system, observe the follow ing guidelines when configuring your
system memory.
• Use only qualified FBDs. FBDs can be either s ingle-ranked or d ual-ranked . FBDs m arked with a 1R are
single
-r anked and modules marked with a 2R are dual -r anked.
• A minimum of two identical FBDs must be installed.
• DIMM sockets must be populated by lowest number first.
• Memory modules m
ust be installed in pairs of matched memory size, speed, and technology , and the
total number of memory modules in the configuration must total two, four, or eight. For best system
performance, all four, or eight memory modules should be identical in size, speed, and technology.
•Memory sp
aring and memory m irroring require e ight memory, and all memory modul es m ust be of
identical memory size, speed, and technology.
• Memory sparing and memory mirroring cannot be implement ed at the same time.
Non-Optimal Memory Configurations
System performance can be affected if your memory configuration does not conform to the preceding
installation guidelines. Your system may issue an error message during startup stating that your memory
configuration is non-optimal.
Memory Sparing Support
The system supports memory sparing if eight identical memory modules are installed in the system. The
memory sparing feature mu st be enabled in the System Setup program and ca n be used only if memory
mirroring is not enabled.( See "Using the System Setup Program " on page 31.)
Memory sparing allocates four ranks of DIMM memory to th e spar e bank. These four ranks consist of the
first rank of memory in DIMM sockets 1 through 4. For single-rank DIMMs, the entire capacity of the four
DIMMs is allocated to sparing whereas for dual-rank DIMMs, only half of the four-DIMM capacity is
allocated to sparing. Table 3-1 shows how memory sparing splits the available and spared memory in each
of the single- and dual-ranked memory module combinations.