IBM 887022X Maintenance Manual - Page 115

Memory modules This section contains instructions on installing, adding, hot-adding, removing, and hot-replacing memory modules. It includes information about memory mirroring and Memory ProteXion features of the Active Memory technology. The following notes describe the types of dual inline memory modules (DIMMs) that the server supports and other information that you must consider when installing DIMMs: v The server comes with a minimum of two 512 MB DIMMs installed in slots 1 and 3 in the SMP Expansion Module and supports 512 MB, 1 GB, and 2 GB DIMMs, for a maximum of 64 GB (mirroring supported) of system memory, depending on your configuration. v IBM periodically makes updates available to provide enhancements to the standard features of the server. Currently, your xSeries 445 supports the Memory Mirroring and Memory ProteXion features of the Active Memory technology. Be sure to check the IBM support Web site occasionally to ensure that you have the most current levels of system software installed. v The hot-add memory feature allows you to add DIMMs without turning off the server. This feature is supported only in those servers using Windows Server 2003 Enterprise or Datacenter editions. Note: You can enable the hot-add and hot-replace memory features or you can enable the fastpath memory feature, but you cannot enable both at the same time. The fastpath memory feature increases memory performance. v To use the hot-add memory feature you must first disable memory mirroring in the Configuration/Setup Utility and there cannot be any DIMMs present in the port in which you want to add DIMMs. v The hot-replace memory feature allows you to replace DIMMs of the same type, size, and clock speed without turning off the server. Note: When memory modules are hot-replaced, the DIMM slots are automatically re-enabled. If the server is turned off when replacing DIMMs, you must re-enable the slots through the Configuration/Setup Utility program (see "Using the Configuration/Setup Utility program" on page 14). v To use the hot-replace memory feature you must enable memory mirroring in the Configuration/Setup Utility. v When using memory mirroring, all of the DIMMs in each memory port must be the same size and clock speed. Note: When memory mirroring is enabled, BIOS will only report half of the installed memory. v Damaged or faulty DIMMs can be replaced without having to replace all the DIMMs in the bank. Ensure the new DIMM is the same size and clock speed as the other DIMMs in the bank. v See the ServerProven list at http://www.ibm.com/pc/compat/ for a list of memory modules for use with the server. For optimum performance balance the amount memory between the two ports. Chapter 4. Installing options 105