Lenovo x3550 M5 - Memory Rank Sparing

•Themaximumavailablememoryisreducedtohalfoftheinstalledmemorywhenmemorymirrored
channelisenabled.Forexample,ifyouinstall64GBofmemoryusingRDIMMs,only32GBof
addressablememoryisavailablewhenyouusememorymirroredchannel.
ThefollowingdiagramliststheDIMMconnectorsoneachmemorychannel.
Microprocessor 2
Microprocessor 1
Channel
CPU1
CPU2
Figure84.Connectorsoneachmemorychannel
Thefollowingtableshowstheinstallationsequenceformemorymirroredchannelmode:
Table28.MemorymirroredchannelmodeDIMMpopulationsequence
DIMMs
Numberofinstalled
microprocessor
DIMMconnectorpopulation
sequenceonthesystemboard
OneMicroprocessor
1stset11,4
2ndset19,12
3rdset12,5
4thset18,11
5thset13,6
6thset17,10
TwoMicroprocessors
1stset21,4
2ndset213,16
3rdset29,12
4thset221,24
5thset22,5
6thset214,17
7thset28,11
8thset220,23
9thset23,6
10thset215,18
11thset27,10
12thset219,22
Memoryranksparing
Thememoryranksparingfeaturedisablesthefailedmemoryfromthesystemconfigurationandactivatesa
ranksparingDIMMtoreplacethefailedactiveDIMM.
164LenovoSystemx3550M5InstallationandServiceGuide