Memory Restrictions; Memory Throughput - IBM IntelliStation POWER 285 Technical Overview And Introduction

2.3.2 Memory restrictions

Attention: Only use IBM memory in IBM System p servers. The IntelliStation POWER 285
system does
exception to this rule. OEM memory is never certified for the use in IBM System p servers.
If the IntelliStation POWER 285 system is populated with OEM memory, you might
experience unexpected and unpredictable behavior.
Examine the label for verification of IBM memory. All IBM memory is identified by an IBM logo
and a white label printed with a barcode on the top and an alphanumeric string on the bottom,
created according to the rule reported in Figure 2-5.
Figure 2-5 IBM memory certification label
Sometimes, OEM vendors put a label reporting the IBM memory part number, but not the
barcode or the alphanumeric string, or both, on their DIMMs.
In the event of a system failure caused by OEM memory installed in the system, the first
recourse is to replace the suspected memory with IBM memory then check whether the
problem is corrected. Contact your IBM representative for further assistance, if needed.

2.3.3 Memory throughput

The memory subsystem throughput is based on the speed of the memory. An elastic
interface, contained in the POWER5+ processor, buffers reads and writes to and from
memory and the processor. There are two Synchronous Memory Interface (SMI-II) chips,
each with a single 8-byte read and 2-byte write high-speed Elastic Interface-II bus to the
processor memory controller. The bus allows double reads or writes per clock cycle. Because
the bus operates at 1066 MHz, the peak processor-to-memory throughput for read is
(8 x 2 x 1056) = 16896 MBps or 16.89. The peak processor-to-memory throughput for write is
(2 x 2 x 1056) = 4224 MBps or 4.22 GBps, making total 21.12 GBps.
The 533 MHz DDR2 memory DIMMS operate at 528 MHz through four 8-byte paths. Read
and write operations share these paths. There must be at least four DIMMs installed to
effectively use each path. In this case, the throughput between the SMI-II and the DIMMs is
(8 x 4 x 528) or 16.89 GBps.
These values are maximum theoretical throughputs for comparison purposes only. Table 2-1
on page 15 provides the theoretical throughputs values for different configurations.
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IBM IntelliStation POWER 285 Technical Overview and Introduction
not
support original equipment manufacturer (OEM) memory. There is no
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IBM plant identificator
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