Installation guide

APPENDIX

Replacing Memory in Cisco 4000 Series Routers C-1

Replacing Memory in

Cisco 4000 Series Routers

This appendix describes how to replace or upgrade memory in a Cisco 4000 series router

and contains the following sections:

• Replacing Main Memory SIMMs

• Replacing Shared-Memory SIMMs

• Replacing the Cisco 4500-M and Cisco 4700-M Boot Helper Flash Memory SIMM

• Replacing Boot ROMs in the Cisco 4000-M

There are two dynamic random-access memory (DRAM) systems in Cisco 4000 series

routers. One is the shared memory, which is the interface that the network processor

modules send data to or transmit data from, and the other is the primary or main memory,

which is reserved for the CPU. In addition, the Cisco 4000-M has Flash memory for storing

the system software image; the Cisco 4500-M and Cisco 4700-M have Flash memory for

the system software image and for the boot helper image.

Caution To avoid damaging ESD-sensitive components, observe all ESD precautions. To

avoid damaging the underlying system card, avoid using excessive force when you remove

or replace SIMMs.

The Cisco 4000-M main memory upgrade requires replacing the main memory

conﬁguration of 4 MB (one 4-MB SIMM) with one 8, 16, or 32-MB SIMM. The

Cisco 4500-M main memory upgrade requires replacing the main memory conﬁguration of

8 MB (two 4-MB SIMMs) with two 8-MB SIMMs or two 16-MB SIMMs.