IBM X3850 X6 User Manual

32 IBM System x3850 X6 and x3950 X6 Planning and Implementation Guide
Since data is moved using both channels at once, additional advanced memory protection
schemes can be implemented to provide protection against both single-bit and multi-bit
errors:
– Chipkill, also known as Single Device Data Correction (SDDC)
– Redundant Bit Steering (RBS)
The combination of these two RAS features is also known as Double Device Data
Correction (DDDC).
Mirroring and sparing are also supported in both modes as described in 2.4.2, “Memory
mirroring and rank sparing” on page 33.
Figure 2-24 shows the two modes. In RAS mode, both channels of one memory buffer are in
lockstep with each other.
Figure 2-24 Memory modes - Performance mode (left) and RAS mode (right)
Table 2-2 shows speed and maximum bandwidth for the SMI2 and DDR3 channels in both
modes.
Table 2-2 Memory mode comparison
Intel Xeon processor
DIMM
Memory
controller
DIMM
DIMM
Memory
controller
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
Memory
buffer
Memory
buffer
Memory
buffer
Memory
buffer
Data 1Data 0
Intel Xeon processor
DIMM
Memory
controller
DIMM
DIMM
Memory
controller
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
DIMM
Memory
buffer
Memory
buffer
Memory
buffer
Memory
buffer
Data
Lockstep
channel
SMI2
links
DDR3
links
Memory performance mode Memory RAS mode
Bus Frequency Transfers/clock Transfer rate Data width Channel bandwidth
Performance mode
SMI2 Bus 1333 MHz 2 2666 MT/s 64 bit 21.3 GB/s
DDR3 Bus 667 MHz 2 1333 MT/s 64 bit 10.7 GB/s
RAS mode
SMI2 Bus 800 MHz 2 1600 MT/s 64 bit 12.8 GB/s
DDR3 Bus 800 MHz 2 1600 MT/s 64 bit 12.8 GB/s

IBM X3850 X6 Specifications

General

Chipset	Intel C602J
Network Controller	Integrated quad-port Gigabit Ethernet
Processor	Up to four Intel Xeon E7-4800 v2 series processors or Intel Xeon E7-8800 v2 series processors
Memory	Up to 6 TB of DDR3 ECC Registered DIMMs (RDIMMs) or Load-Reduced DIMMs (LRDIMMs)
Form Factor	4U rack server
Storage	Up to 24x 2.5" hot-swap SAS/SATA HDDs or SSDs
Expansion Slots	Up to 11 PCIe 3.0 slots
Power Supply	Up to four 1400W or 900W hot-swap power supplies
Memory Type	DDR3 RDIMM/LRDIMM
Storage Controller	ServeRAID M5210 SAS/SATA controller
RAID Support	RAID 0, 1, 5, 6, 10, 50, 60
Operating System Support	Windows Server, Red Hat Enterprise Linux, SUSE Linux Enterprise Server, VMware