70 IBM eX5 Implementation GuideThe MAX5 is connected to the x3850 X5 using four cables, connecting the QPI ports on theserver to the four QPI ports on the MAX5. Figure 3-12 shows architecturally how asingle-node x3850 X5 connects to a MAX5.Figure 3-12 The x3850 X5: Connectivity of the system unit with the MAX5We describe the connectivity of the MAX5 to the x3850 X5 in 3.6, “Scalability” on page 70.For memory configuration information, see 3.8.4, “Memory mirroring” on page 87. Forinformation about power and fans, see 3.14, “Power supplies and fans of the x3850 X5 andMAX5” on page 112.3.6 ScalabilityIn this section, we describe how to expand the x3850 X5 to increase the number ofprocessors and the number of memory DIMMs.The x3850 X5 currently supports the following scalable configurations: A single x3850 X5 server with four processor sockets. This configuration is sometimesreferred to as a single-node server. A single x3850 X5 server with a single MAX5 memory expansion unit attached. Thisconfiguration is sometimes referred to as a memory-expanded server.SMIlinksQPIlinksIntelXeonCPU 3IntelXeonCPU 1IntelXeonCPU 4IntelXeonCPU 2ExternalQPI cablesSystem x3850 X5 MAX5QPIQPIQPI QPIEXAQPI QPIQPI EXA EXA EXAQPIQPITip: As shown in Figure 3-12 on page 70, you maximize performance when you have fourprocessors installed, because you then have four active QPI links to the MAX5. However,configurations of two and three processors are still supported. If only two processors arerequired, consider the use of the x3690 X5.
