IBM X3850 X6 User Manual

Chapter 3. Product information 71
3.8.2 Memory population order
The x3850 X6 and x3950 X6 servers have two main memory operation modes: Performance
mode and RAS (Lockstep) mode, and also two additional modes: Mirroring and Rank
Sparing.
The main operation modes can be combined with additional modes, so overall there can be
six operation modes:
򐂰 Performance (also referred to as Independent mode)
򐂰 RAS (also referred to as Lockstep mode)
򐂰 Performance + Mirroring
򐂰 Performance + Rank Sparing
򐂰 RAS + Mirroring
򐂰 RAS + Rank Sparing
For more information about memory operation modes, see 2.4.1, “Operational modes” on
page 31 and 2.4.2, “Memory mirroring and rank sparing” on page 33.
Depending on selected operating mode, you should use the appropriate DIMMs installation
order. Table 3-7 shows the DIMMs placement order depending on operation mode.
The DIMM installation order for Rank Sparing mode follows the Performance mode or RAS
(Lockstep) mode installation order as specified before, based on the operation mode
selected.
2 DIMMs / channel 1333 MHz 1333 MHz 1333 MHz 1333 MHz 1333 MHz 1333 MHz 1333 MHz 1333 MHz
3 DIMMs / channel
1066 MHz 1333 MHz 1066 MHz 1333 MHz 1333 MHz 1333 MHz 1333 MHz 1333 MHz
Maximum operating speed - RAS mode (1:1 mode - SMI2 link operates at the DDR3 speed shown)
1 DIMM / channel
1333 MHz 1600 MHz 1333 MHz 1600 MHz 1333 MHz 1600 MHz 1333 MHz 1333 MHz
2 DIMMs / channel
1333 MHz 1600 MHz 1333 MHz 1600 MHz 1333 MHz 1600 MHz 1333 MHz 1333 MHz
3 DIMMs / channel
1066 MHz 1333 MHz 1066 MHz 1333 MHz 1333 MHz 1333 MHz 1333 MHz 1333 MHz
a. Maximum memory capacity for the x3850 X6 server / Maximum memory capacity for the x3950 X6 server.
DIMM
specification
RDIMM LR-DIMM

IBM X3850 X6 Specifications

General

Brand	IBM
Model	X3850 X6
Category	Server
Language	English