106 Installing System Components
System Memory
Your system supports DDR3 unbuffered ECC DIMMs (UDIMMs) and 
registered ECC DIMMs (RDIMMs). DIMMs can be 1066 or 1333 MHz. 
The system contains six memory sockets organized into two DDR3 channels. 
The first socket of each channel is marked with white release levers.
General Memory Module Installation Guidelines
To ensure optimal performance of your system, observe the following general 
guidelines when configuring your system memory.
  NOTE: Memory configurations that fail to observe these guidelines can prevent 
your system from starting and producing any video output. 
• Except for memory channels that are unused, all populated memory 
channels must have identical configurations.
• Memory modules of different sizes can be mixed in sockets 1 to 6 
(for example, 2 GB and 4 GB), but all populated channels must have 
identical configurations.
• Memory modules are installed in the numeric order of the sockets 
beginning with 1 to 6.
• If memory modules with different speeds are installed, they will operate at 
the speed of the slowest installed memory module(s).
Mode-Specific Guidelines
Your system supports both single-channel and dual-channel modes. A 
minimal single-channel configuration of one 1 GB memory module is also 
supported in this mode.
Table 3-2 shows sample memory configurations that follow the appropriate 
memory guidelines stated in this section. The samples show identical 
memory-module configurations and their physical and available memory 
totals. The table does not show mixed- or quad-rank memory-module 
configurations, nor does it address the memory speed considerations of any 
configuration.
R310HOM.book  Page 106  Thursday, March 4, 2010  1:03 AM