Lenovo HS22V Betriebsanweisung PDF herunterladen (Seite 8)

High-performance blade server optimized for virtualization

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1333MHz, the improvement is almost 500% over the previous generation. This huge

improvement is mainly due to the dual integrated memory controllers and faster DDR3 1333MHz

memory. Throughput at 800MHz is 25 gigabytes per second (GBps); at 1066MHz it’s 32GBps;

and at 1333MHz it’s 35GBps. This improvement translates into improved application

performance and scalability.

Memory interleaving refers to how physical memory is interleaved across the physical DIMMs. A

balanced system provides the best interleaving. A Xeon 5600 processor-based system is

balanced when all memory channels for a socket have the same amount of memory.

In the case of HS22V, which has a balanced DIMM layout, it is easy to balance the system for all

three memory frequencies. The recommended DIMM population is shown below, assuming

DIMMs with identical capacities.

Memory

Frequency

DIMMs per

Channel

Max. Memory

Capacity

5600 Series 5500 Series

1333MHz

(12 DIMMs)

192GB RDIMM

X5650, L5640,

E5645 and

above

N/A

1066MHz

(18 DIMMs)

288GB RDIMM All N/A

800MHz

(18 DIMMs)

288GB RDIMM N/A E5503/E5507

800MHz-

1333MHz

(Mirroring)

(12 DIMMs)

96GB RDIMM All processors All processors

A memory rank is simply a segment of memory that is addressed by a specific address bit.

DIMMs typically have 1, 2 or 4 memory ranks, as indicated by their size designation.

A typical memory DIMM description is 2GB 2Rx8 DIMM:

 The 4R designator is the rank count for this particular DIMM (R for rank = 2)

 The x8 designator is the data width of the rank

It is important to ensure that DIMMs with appropriate number of ranks are populated in each

channel for optimal performance. Whenever possible, it is recommended to use dual-rank

DIMMs in the system. Dual-rank DIMMs offer better interleaving and hence better performance

than single-rank DIMMs. For instance, a system populated with six 2GB dual-rank DIMMs

outperforms a system populated with six 2GB single-rank DIMMs by 7% for SPECjbb2005. Dual-

rank DIMMs are also better than quad-rank DIMMs because quad-rank DIMMs will cause the

memory speed to be down-clocked.

Another important guideline is to populate equivalent ranks per channel. For instance, mixing

one single-rank DIMM and one dual-rank DIMM in a channel should be avoided.

Note: It is important to ensure that all three memory channels in each processor are populated.

The relative memory bandwidth decreases as the number of channels populated decreases. This

is because the bandwidth of all the memory channels is utilized to support the capability of the

processor. So, as the channels are decreased, the burden to support the requisite bandwidth is

increased on the remaining channels, causing them to become a bottleneck.

For peak performance:

 Always populate both processors with equal amounts of memory to ensure a balanced

NUMA system.

 Always populate all 3 memory channels on each processor with equal memory capacity.

 Populate an even number of ranks per channel.

 Use dual-rank DIMMs whenever appropriate.

 For optimal 1333MHz performance, populate with 12 dual-rank DIMMs (3 per processor, 2

per channel) for processsors that support 2 DIMMs per Channel (2DPC).

 For optimal 1066MHz performance, populate with 12 dual-rank DIMMs (6 per processor, 2

per channel).

 For optimal 800MHz performance with high DIMM counts, populate with 18 dual-rank or

quad-rank DIMMs (9 per processor) and clock memory down to 800MHz in BIOS.

 With the above rules, it is not possible to have a performance-optimized system with 4GB,

8GB, 16GB, or 128GB. With 3 memory channels and interleaving rules, configure systems

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