Cisco PRP-1= Installation And Configuration Manual page 13

SDRAM
Caution
SRAM
NVRAM
OL-11656-01
SDRAM stores routing tables, protocols, and network accounting applications,
and runs the Cisco IOS software. The default PRP-1 configuration includes 512
MB of error checking and correction (ECC) SDRAM. DIMM upgrades of 512 MB
and 1 GB are available for the PRP-1. You cannot mix memory sizes. If two
DIMMS are installed, they must be the same memory size.
The default PRP-2 configuration includes 1 GB of ECC SDRAM. DIMM
upgrades of 1 GB and 2 GB are available for the PRP-2. You can mix memory
sizes as long as the larger DIMM is placed in bank 1 (U15).
Only Cisco-approved memory is supported. Do not attempt to install other devices
or non-Cisco approved DIMMs in the DIMM sockets. (See
SRAM provides 2 MB of parity-protected, secondary CPU cache memory. Its
principal function is to be a staging area for routing table updates and for
information sent to and from line cards. SRAM is not user configurable or field
replaceable.
NVRAM provides 2 MB of memory for system configuration files, software
configuration register settings, and environmental monitoring logs. This
information is backed up with built-in lithium batteries that retain the contents for
a minimum of 5 years. NVRAM is not user configurable or field replaceable.
Performance Route Processor Installation and Configuration Guide
Product Overview
Table 15 on page 75.)
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