Installing System Components 99• For Optimizer Mode, memory modules are installed in the numeric orderof the sockets beginning with A1 or B1.• For Memory Mirroring or Advanced ECC Mode, the socket furthest fromthe processor is unused and memory modules are installed beginning withsocket A1 or B1 and proceeding with socket A2 or B2.• Advanced ECC Mode requires memory modules that use x4 or x8 DRAMdevice widths.• The memory speed of each channel depends on the memoryconfiguration:– For single or dual-rank memory modules:• One memory module per channel supports up to 1333 MHz.• Two memory modules per channel supports up to 1067 MHz.• Three memory modules per channel supports up to 800 MHz,regardless of memory module speed.– For quad-rank memory modules:• One memory module per channel supports up to 1067 MHz.• Two memory modules per channel are limited to 800 MHz,regardless of memory module speed.• If quad-rank memory modules are mixed with single- or dual-rankmodules, the quad-rank modules must be installed in the sockets with thewhite release levers.• If memory modules with different speeds are installed, they will operate atthe speed of the slowest installed memory module(s).Mode-Specific GuidelinesThree memory channels are allocated to each processor. The number ofchannels and allowable configurations depend on the memory mode selected.Advanced ECC (Lockstep) Mode SupportIn this configuration, the two channels closest to the processor are combinedto form one 128-bit channel. This mode supports SDDC for both x4- and x8-based memory modules. Memory modules must be identical in size, speed,and technology in corresponding slots.
