80 Installing System ComponentsSystem MemoryYour system supports DDR3 ECC unbuffered memory modules (UDIMMs).The DIMMs can be 1066 or 1333-MHz. Single and dual-rank DIMMs can be1066 or 1333-MHz.The system contains four memory sockets, each two-socket set is organizedinto two channels. The first socket of each channel is marked with whiterelease levers.General Memory Module Installation GuidelinesTo ensure optimal performance of your system, observe the following generalguidelines when configuring your system memory.NOTE: Memory configurations that fail to observe these guidelines can preventyour system from starting or producing any video output.• Except for memory channels that are unused, all populated memorychannels must have identical configurations.• Memory modules of different sizes can be mixed within a memory channel(for example, 2-GB and 4-GB), but all populated channels must haveidentical configurations.• Memory modules are installed in the numeric order of the socketsbeginning with DIMM_A1 or DIMM_B1.• One or two DIMMs per channel can support up to 1333-Mhz.• If memory modules with different speeds are installed, they operate at thespeed of the slowest installed memory module(s).Mode-Specific GuidelinesYour system supports both single-channel and dual-channel mode. A minimalsingle-channel configuration of one 1-GB memory module is also supportedin this mode.Table 3-2 shows sample memory configurations that follow the appropriatememory guidelines stated in this section. The samples show identicalmemory-module configurations and their the physical and available memorytotals. The table does not show mixed memory-module configurations, nordo they address the memory speed considerations of any configuration.
