Cisco 2x32GB PC-12800 UCS-ML-2X324RY-E Benutzerhandbuch
Produktcode
UCS-ML-2X324RY-E
Cisco UCS C460 M4 High-Performance Rack-Mount Server
18
CONFIGURING the SERVER
— Memory Performance Mode. In this mode, the main memory channel from the CPU
to the memory buffer runs at double the clock rate of each of the two memory
subchannels from the buffer to the DIMMs, and each DIMM subchannel is accessed
sequentially. For example, if the CPU channel clock speed is 2667 MHz, each of the
DIMM subchannels operates at 1333 MHz. For this reason, performance mode is
referred to as 2:1. Performance mode does not provide data protection, but can
yield up to 1.5 times the performance of lockstep mode and is the best choice for
high throughput requirements.
subchannels from the buffer to the DIMMs, and each DIMM subchannel is accessed
sequentially. For example, if the CPU channel clock speed is 2667 MHz, each of the
DIMM subchannels operates at 1333 MHz. For this reason, performance mode is
referred to as 2:1. Performance mode does not provide data protection, but can
yield up to 1.5 times the performance of lockstep mode and is the best choice for
high throughput requirements.
— Memory Lockstep Mode. In this mode, the main memory channel from the CPU to
the memory buffer runs at the same clock rate of each of the two memory
subchannels from the buffer to the DIMMs, and both DIMM subchannels are accessed
simultaneously for a double-width access. For example, if the CPU channel clock
speed is 1600 MHz, each of the DIMM subchannels operates at 1600 MHz. For this
reason, lockstep mode is referred to as 1:1. Memory lockstep mode provides
protection against both single-bit and multi-bit errors. Memory lockstep lets two
memory channels work as a single channel, moving a data word two channels wide
and providing eight bits of memory correction.
subchannels from the buffer to the DIMMs, and both DIMM subchannels are accessed
simultaneously for a double-width access. For example, if the CPU channel clock
speed is 1600 MHz, each of the DIMM subchannels operates at 1600 MHz. For this
reason, lockstep mode is referred to as 1:1. Memory lockstep mode provides
protection against both single-bit and multi-bit errors. Memory lockstep lets two
memory channels work as a single channel, moving a data word two channels wide
and providing eight bits of memory correction.
■
CPU Effect on DIMM Performance
■
DIMM Clock Speeds
DIMMs run at various clock speeds depending on the DIMM voltage and number of DIMMs
per channel. See
and
.
Table 7
CPU Effect on DIMM Performance
CPU Memory Mode
Advanced CPU
1
8.0 GT/s QPI
Notes . . .
1. CPU examples: E7-4890/4880/4870/4860 v2, E7-8893/8891/8857 v2
Standard CPU
2
7.2 GT/s QPI
2. CPU examples: E7-4850/4830/4820 v2
Basic CPU
3
6.4 GT/s QPI
3. CPU example: E7-4809 v2
Lockstep Mode (1:1)
1600 MHz
1600 MHz
1333 MHz
Performance Mode (2:1)
1333 MHz
1066 MHz
1066 MHz
Table 8
DIMM Performance (at 1.5 V)
DIMM GB/Rank/Type
Performance Mode (2:1)
1.5 V DIMM
Lockstep Mode (1:1)
1.5 V DIMM
1 DPC
2 DPC
3 DPC
1 DPC
2 DPC
3 DPC
8 GB/2R/RDIMM
1333 MHz
1333 MHz
1066 MHz
1333 MHz
1333 MHz
1066 MHz
16 GB/2R/RDIMM
1333 MHz
1333 MHz
1066 MHz
1333 MHz
1333 MHz
1066 MHz
32 GB/4R/LRDIMM
1333 MHz
1333 MHz
1333 MHz
1600 MHz
1600 MHz
1333 MHz
64 GB/8R/LRDIMM
1066 MHz
1066 MHz
1066 MHz
1066 MHz
1066 MHz
1066 MHz