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Dell PowerEdge Servers

Dell PowerEdge T710

I had suspected that the Dell PowerEdge T710 has 2 IOH devices to support the PCI-E slot configuration, with the alternative being the use of PCI-E expanders. For a while, I could not find an explicit reference, but it is the Dell T710 Technical Reference, as shown below.

PCI-E

Dell PowerEdge 11th Generation Servers: R810, R910 and M910 Memory Guidance

Dell put out the following paper on the Dell PowerEdge 11th Generation Servers: R810, R910, and M910 Memory Guidance

When the R810 was first announced, I thought it was strictly a 2-way system. It turns out to be a hybrid 2 or 4-way server, but from the Dell website, I cannot seem to order the R810 with more than 2 processors. The R810 can be purchased with either 1 or 2 processor sockets populated. Both the R910 and M910 are 4-way servers. The Dell M910 is a 4-way blade server for the Xeon 7500 series processor line.

The R910 and M910 can be purchased with either 2 or 4 processor sockets populated, but not 1 or 3. Both the R810 and M910 have up to 32 DIMM sockets. The R910 can have up to 64 DIMM sockets.

The Dell whitepaper refers to both the R810 and M910 are 4-ways servers, and the only one of two memory controllers on each CPU are used in the four-CPU configuration. In the two-CPU configuration, the FlexMem bridge is used to connect to DIMM sockets that would otherwise connect to the processors in the unpopulated sockets. In the 2 processor sockets populated configuration, both memory controllers on each processor are used, with one memory controller connecting to local memory, and the second controller connected to memory on one of the unpopulated processor sockets. The Anandtech article High-End x86: The Nehalem EX Xeon 7500 and Dell R810 voices serious complaints on this.

FlexMem 1a

The Figure below shows the complete system with either 2 or 4 processor sockets populated. When only two processors are present, the FlexMem Bridge reroutes the memory signals.

FlexMem 2

The Dell whitepaper explicitly states that on the R910, the memory riser card is only connected if its associated processor socket is populated. Both memory controllers on each processor are used so long as each memory riser is populated. The Dell whitepaper provides further elaboration on the DIMM configuration to achieve maximum memory bandwidth. The diagram below from the whitepaper shows a representation of the Dell PowerEdge R910. Each riser has 8 DIMM sockets, and two risers are pair with each processor. With two processor sockets populated, there are 32 DIMM sockets. With all four processors populated, the full set of 64 DIMM sockets are present.

FlexMem 3

On the Dell website, if one were to order the R810 with one processor socket, then only 16 DIMM sites are listed as available. All 32 DIMM sites are available with two processors.