HP Server rp7420 HP 9000 rp7420 Server - User Service Guide, Fifth Edition - Page 23

Figure 1-7 Memory Subsystem PDH Riser Board The Platform Dependant Hardware Riser board is a daughter card for the cell board. It contains a micro-processor memory interface microcircuit, processor-dependent hardware including the processor-dependent code (PDC), flash memory, and a manageability microcontroller, called the Platform Dependant Hardware Controller (PDHC) with associated circuitry. The PDH obtains cell board configuration information from cell board signals and from the LPM on the cell. The PDH riser board contains circuitry that the cell board requires to function and, therefore, each cell board must have a PDH riser installed before it is added to a server. Central Processor Units The cell board can hold up to eight (four dual-core) CPUs and can be populated with CPUs in increments of two CPUs. On a cell board, the processors must be the same type and speed. Two CPUs is the minimum configuration allowed on the HP 9000 rp7420 server. There are two Frontside Buses (FBS), one for sockets 0 and 1, and one for sockets 2 and 3. Each FBS must have either a CPU or a terminator at the end of the bus or the board does not operate properly. There cannot be a terminator board in socket 1 or socket 3 locations. For the CPU load order that must be maintained when adding CPUs to the cell board, see Table 1-2. For the locations on the cell board for installing CPUs, see Figure 1-8. Table 1-2 Cell Board CPU Load Order Number of Socket 0 Location CPUs Installed Two CPU installed Four CPU installed Socket 1 Location Empty slot Empty slot Socket 2 Location Terminator CPU installed Socket 3 Location Empty Empty Detailed HP 9000 rp7420 Server Description 23