HP Integrity rx7640 Site Preparation Guide, Fourth Edition - HP Integrity rx76 - Page 19

Because of space limitations on the cell board, the PDH and microcontroller circuitry resides on a riser board that plugs into the cell board at a right angle. The cell board also includes clock circuits, test circuits, and de-coupling capacitors. PDH Riser Board The PDH riser board is a small card that plugs into the cell board at a right angle. The PDH riser interface contains the following components: • Microprocessor memory interface microcircuit • Hardware including the processor dependant code (PDH) flash memory • Manageability microcontroller with associated circuitry The PDH obtains cell board configuration information from cell board signals and from the cell board local power module (LPM). Central Processor Units The cell board can hold up to four CPU modules. Each CPU module can contain up to two CPU cores on a single socket. Modules are populated in increments of one. On a cell board, the processor modules must be the same family, type, and clock frequencies. Mixing of different processors on a cell board or partition is not supported. Refer to Table 1-1 for the load order that must be maintained when adding processor modules to the cell board. Refer to Figure 1-8 for the locations on the cell board for installing processor modules. NOTE: Unlike previous HP cell based systems, the HP Integrity rx7640 server cell board does not require that a termination module be installed at the end of an unused FSB. System firmware is allowed to disable an unused FSB in the CC. This enables both sockets of the unused bus to remain unpopulated. Table 1-1 Cell Board CPU Module Load Order Number of CPU Modules Installed Socket 2 1 Empty slot 2 CPU installed 3 CPU installed 4 CPU installed Socket 3 Empty slot Empty slot Empty slot CPU installed Socket 1 Empty slot Empty slot CPU installed CPU installed Socket 0 CPU installed CPU installed CPU installed CPU installed Detailed Server Description 19