IBM System x3250 M4 Installation & User Manual

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IBM System x3250 M4 Installation & User Manual Manual pdf 49 page image

1 = single-rank2 = dual-rank4 = quad-rankff is the device organization (bit width)4 = x4 organization (4 DQ lines per SDRAM)8 = x8 organization16 = x16 organizationwwwww is the DIMM bandwidth, in MBps8500 = 8.53 GBps (PC3-1066 SDRAMs, 8-byte primary data bus)10600 = 10.66 GBps (PC3-1333 SDRAMs, 8-byte primary data bus)12800 = 12.8 GBps (PC3-1600 SDRAMs, 8-byte primary data bus)m is the DIMM typeE = Unbuffered DIMM (UDIMM) with ECC (x72-bit module data bus)R = Registered DIMM (RDIMM)U = Unbuffered DIMM with no ECC (x64-bit primary data bus)aa is the CAS latency, in clocks at maximum operating frequencybb is the JEDEC SPD Revision Encoding and Additions levelcc is the reference design file for the design of the DIMMNotes:1. To determine the type of a DIMM, see the label on the DIMM. Theinformation on the label is in the format xxxxx nRxxx PC3-xxxxx-xx-xx-xxx.The numeral in the sixth numerical position indicates whether the DIMM issingle-rank (n=1) or dual-rank (n=2).2. The amount of usable memory is reduced, depending on the systemconfiguration. A certain amount of memory must be reserved for systemresources. To view the total amount of installed memory and the amount ofconfigured memory, run the Setup utility. For additional information, seeChapter 3, “Configuring the server,” on page 51.The following sections provide additional information specific to unbuffered andregistered DIMMs that you must consider.Unbuffered DIMMs (UDIMMs)The following notes provide information that you must consider when you installUDIMMs:v The memory channels run at the lowest common frequency of the DIMMsinstalled.v The UDIMM options that are available for the server are 1 GB, 2 GB, 4 GB, and8 GB (when available) DIMMs.v The server supports up to two single-rank or dual-rank UDIMMs per channel.v The following table lists the supported UDIMM population.Table 4. Supported UDIMM population per channelDIMMconnectors perchannelDIMMs installedin each channel DIMM type DIMM speedRanks perDIMM (anycombination)2 1 UnbufferedDDR3 ECC1066, 1333,1600Single-rank,dual-rankChapter 2. Installing optional devices 31