Installation Guide, Sixth Edition - HP Integrity rx8620 Server

Chapter 1
Introduction
Detailed HP Integrity rx8620 Server Description
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The HP Integrity rx8620 Server will support DIMMs with densities of 64, 128, 256, and 512Mb for the
SDRAM devices. Table 1-2 shows each supported DIMM size, the resulting total server capacity, and the
memory component density. Each DIMM is connected to two buffer chips on the cell board.
Main Memory Performance
Latency to main memory is an important parameter in determining overall system performance. For a server
with memory busses at 125MHz, the latency for a page hit is 8.5 cycles (68ns), the latency for a page closed is
11.5 cycles (92ns), and the latency for a page miss is 14.5 cycles (116ns).
Valid Memory Configurations
The HP Integrity rx8620 Server is capable of supporting as little as 0.5GB of main memory using two 256MB
DIMMs installed on one of the cell boards and as much as 128GB by filling all 16 DIMM slots on all four cell
boards with 2GB DIMMs.
DIMMs must be loaded in sets of two at specified locations on the cell board. Two DIMMs are called an
“echelon”, so two echelons would be equivalent to four DIMMs, three echelons would be equivalent to six
DIMMs and so on. The DIMMs must be the same size in an echelon. The DIMMs across all cells in a partition
should have identical memory loaded. Figure 1-8 shows the DIMM slot layout on the cell board. See Table 1-3
and Figure 1-8 for DIMM load order and layout on the cell board.
Table 1-2 HP Integrity rx8620 Server DIMMs
DIMM Size
Total HP Integrity
rx8620 Server Capacity
Memory Component Density
256MB 16GB 64Mb
512MB 32GB 128Mb
1GB 64GB 256Mb
2GB 128GB 512Mb
4GB 256GB 1024Mb