Figure 12. Diagram Of Flexmem Bridge Routing - Dell External OEMR R810 Technical Manual

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to four DDR3 DIMMs. In a typical Intel Xeon processor 6500/7500 series configuration, only the

memory buffers associated with the two populated sockets would be connected, and therefore only

16 DIMMs would be accessible.

To overcome this limitation with 2 CPUs, the R810 uses the FlexMem Bridge which allows CPU1 and

CPU2 to connect to the memory of their respective adjacent sockets (CPU3 and CPU4). The FlexMem

Bridge provides the following:



Two pass-through links for SMI



One pass-through link for QPI

The pass-through SMI links connect the two installed CPU's to additional SMIs, therefore the CPU's

will have the following memory attached:



CPU1 will have access to DIMMs [A1:A8], plus DIMMs [C1:C8] (those normally associated

with CPU3)



CPU2 will have access to DIMMs [B1:B8], plus DIMMs [D1:D8] (those normally associated

with CPU4)

The pass-through QPI link on the FlexMem Bridge provides increased performance for a 2P

configuration because it allows 2 full-bandwidth QPI links between CPU1 and CPU2 as opposed to a

single link. Figure 12 depicts the interconnection between the CPU sockets as well as connections

internal to the FlexMem Bridges. The FlexMem Bridges are only supported in sockets 3 and 4.

Modern processors are capable of tremendous workloads, and many types of utilization patterns such

as virtualization often run into memory capacity issues well before the processors reach a saturation

point. FlexMem Bridge technology was designed to assist those customers that have workloads that

are memory intensive.

Customers who scale their workloads in the future to a point where they would need additional

processing power can simply replace the FlexMem Bridge with additional processors to meet those

needs.

Due to power limitations, the PowerEdge R810 will only support two X7560 (130W) processors. In an

upgrade for a server with two 130W CPUs, the CPUs and the heatsink must be changed to the 95W or

105W CPUs. If the server has only the 95W or 105W CPUs, CPUs can simply be swapped out.

Dell PowerEdge R810 Technical Guide