Upgrading Your Server 11-17Using the Memory RAS FeaturesThe server has RAS feature including "Standard memory configuration (x4 SDDC ECC memory)and "LockStep (x8 SDDC ECC memory) feature. SDDC (Single Device Correction) allowsautomatic correction of memory error (multi-bit error).IMPORTANT: To use x4 SDDC ECC memory feature, additional 2-GB/4-GBmemory board is required. The factory-installed two 1-GB DIMMsand additional 1-GB memory board is unavailable for x4 SDDCfeature. "LockStep (x8 SDDC ECC memory) feature cannot be usedtogether with "Standard memory configuration (x4 SDDC ECCmemory)The memory area on the motherboard of the server is divided into two memory channels as shownin the figure below.The LockStep feature keeps memory redundancy between memory channels by monitoring oraltering memory active/inactive status, respectively.CPU1Memory controllerCH0 CH1CPU1_DIMM 3 CPU1_DIMM 4CPU1_DIMM 1 CPU1_DIMM 2CPU2Memory controllerCH0 CH1CPU2_DIMM 3 CPU2_DIMM 4CPU2_DIMM 1 CPU2_DIMM 2
