Intel ® Quickpath Interconnect; Integrated Memory Controller (Imc) And Memory Subsystem - Intel S2400SC Technical Product Specification

Functional Architecture
3.2.1 Intel QuickPath Interconnect
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The Intel QuickPath Interconnect is a high speed, packetized, point-to-point interconnect used
in the processor. The narrow high-speed links stitch together processors in distributed shared
memory and integrated I/O platform architecture. It offers much higher bandwidth with low
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latency. The Intel QuickPath Interconnect has an efficient architecture allowing more
interconnect performance to be achieved in real systems. It has a snoop protocol optimized for
low latency and high scalability, as well as packet and lane structures enabling quick
completions of transactions. Reliability, availability, and serviceability features (RAS) are built into
the architecture.
The physical connectivity of each interconnect link is made up of twenty differential signal pairs
plus a differential forwarded clock. Each port supports a link pair consisting of two uni-directional
links to complete the connection between two components. This supports traffic in both
directions simultaneously. To facilitate flexibility and longevity, the interconnect is defined as
having five layers: Physical, Link, Routing, Transport, and Protocol.
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The Intel QuickPath Interconnect includes a cache coherency protocol to keep the distributed
memory and caching structures coherent during system operation. It supports both low-latency
source snooping and a scalable home snoop behavior. The coherency protocol provides for
direct cache-to-cache transfers for optimal latency.
3.2.2

Integrated Memory Controller (IMC) and Memory Subsystem

Integrated into the processor is a memory controller. Each processor provides three DDR3
channels that support the following:
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Unbuffered DDR3 and registered DDR3 DIMMs
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Independent channel mode or lockstep mode
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Data burst length of eight cycles for all memory organization modes
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Memory DDR3 data transfer rates of 800, 1066, 1333, and 1600 MT/s
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64-bit wide channels plus 8-bits of ECC support for each channel
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DDR3 standard I/O Voltage of 1.5 V and DDR3 Low Voltage of 1.35 V
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1-Gb, 2-Gb, and 4-Gb DDR3 DRAM technologies supported for these devices:
o UDIMM DDR3 – SR x8 and x16 data widths, DR – x8 data width
o RDIMM DDR3 – SR and DR – x4 and x8 data widths
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Up to 4 ranks supported per memory channel, 1 or 2 ranks per DIMM
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Open with adaptive idle page close timer or closed page policy
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Per channel memory test and initialization engine can initialize DRAM to all logical zeros
with valid ECC (with or without data scrambler) or a predefined test pattern
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Isochronous access support for Quality of Service (QoS)
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Minimum memory configuration: independent channel support with 1 DIMM populated
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Integrated dual SMBus* master controllers
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Command launch modes of 1n/2n
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RAS Support:
o Rank Level Sparing and Device Tagging
o Demand and Patrol Scrubbing
22 Intel order number G36516-002
Intel® Server Board S2400SC TPS
Revision 2.0