68 IBM eX5 Implementation Guide
The QPI Wrap Cards are not included with standard server models and must be ordered
separately. See Table 3-5.
Table 3-5 Ordering information for the QPI Wrap Card
The QPI Wrap Cards are installed in the QPI bays at the back of the server, as shown in
Figure 3-10.
QPI Wrap Cards are not needed in a 2-node configuration and not needed in a MAX5
configuration. When the QPI Wrap Cards are installed, no external QPI ports are available.
If you later want to attach a MAX5 expansion unit or connect a second node, you must first
remove the QPI Wrap Cards.
Figure 3-10 Rear of the x3850 X5
3.5 MAX5
As introduced in 3.1.3, “IBM MAX5 memory expansion unit” on page 59, the MAX5 memory
expansion drawer is available for both the x3850 X5 and the x3950 X5. Models of the x3850
X5 and x3950 X5 are available that include the MAX5, as described in 3.3, “Models” on
Part number Feature code Description
49Y4379 Not applicable IBM x3850 X5 and x3950 X5 QPI Wrap Card Kit (quantity 2)
Tips:
򐂰 Part number 49Y4379 includes two QPI Wrap Cards. You order only one of these parts
per server.
򐂰 QPI Wrap Cards cannot be ordered individually.
QPI bays (remove
the blanks first)
Chapter 3. IBM System x3850 X5 and x3950 X5 69
page 64, Also, you can order the MAX5 separately, as listed in Table 3-6. When ordering a
MAX5, remember to order the cable kit as well. For power supply fault redundancy, order the
optional power supply.
Table 3-6 Ordering information for the IBM MAX5 for System x
The eX5 chip set in the MAX5 is an IBM unique design that attaches to the QPI links as a
node controller, giving it direct access to all CPU bus transactions. It increases the number of
DIMMs supported in a system by a total of 32, and it also adds another 16 channels of
memory bandwidth, boosting overall throughput. Therefore, the MAX5 adds additional
memory and performance.
The eX5 chip connects directly through QPI links to all of the CPUs in the x3850 X5, and it
maintains a directory of each
CPU’s last-level cache. Therefore, when a CPU requests
content stored in the cache of another CPU, the MAX5 not only has that same data stored in
its own cache, it is able to return the acknowledgement of the snoop
and the data to the
requesting CPU in the same transaction. For more information about QPI links and snooping,
see 2.2.4, “QuickPath Interconnect (QPI)” on page 18.
The MAX5 also has EXA scalability ports used in an EXA-scaled configuration (that is, a
2-node and MAX5 configuration). These ports are reserved for future use.
In summary, the MAX5 offers the following major features:
򐂰 Adds 32 DIMM slots to either the x3850 X5 or the x3690 X5
򐂰 Adds 16 channels of memory bandwidth
򐂰 Improves snoop latencies
Figure 3-11 shows a diagram of the MAX5.
Figure 3-11 MAX5 block diagram
Part number Feature code Description
59Y6265 4199 IBM MAX5 for System x
60Y0332 4782 IBM 675W HE Redundant Power Supply
59Y6267 4192 IBM MAX5 to x3850 X5 Cable Kit
SMI
links
DDR3 DIMMs
(Two DIMMs per channel)
Memory
buffer
Memory
buffer
Memory
buffer
Memory
buffer
SMI
links
Memory
buffer
Memory
buffer
Memory
buffer
Memory
buffer
DDR3 DIMMs
(Two DIMMs per channel)
External connectors
QPI QPIQPI QPI EXA EXA EXA
IBM EXA
chip
QPI QPI

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