Installation guide

6
Upgrading System Memory in Cisco 3600 Series Routers
78-3636-05
Memory Configurations
SDRAM DIMMs (Cisco 3631 and Cisco 3660 Routers)
Cisco 3631 and Cisco 3660 routers each contain two DIMM sockets for SDRAM: bank 0 (DIMM 0) and
bank 1 (DIMM 1). A socket corresponds to one bank of memory. Each socket can hold one SDRAM
DIMM of any size permitted for that router. The other socket can optionally be left empty.
Banks must be filled in the following order:
• Cisco 3631: Fill in any order.
• Cisco 3660: Fill from bank 0, and empty from bank 1. Bank 0 must always be filled first and
emptied last.
DIMM parity is as follows:
• Cisco 3631: Nonparity DIMMs
• Cisco 3660: Both parity and nonparity DIMMs
Note An advantage to using parity DIMMs compared to nonparity DIMMs is easier identification
of memory errors. A disadvantage is lower performance.
Only certain combinations of SDRAM DIMM sizes are permitted:
• Cisco 3631: There is no limitation on the relative size of DIMMs in bank 1 and bank 0, as shown in
Table 5.
• Cisco 3660: The DIMM in bank 1 must be the same size as or smaller than the DIMM in bank 0, as
shown in Table 6.
16 MB 16 MB 16 MB 16 MB 64 MB
32 MB-Dual
3
32 MB-Dual — —
32 MB-Dual 32 MB-Dual 4 MB 4 MB 72 MB
32 MB-Dual 32 MB-Dual 8 MB 8 MB 80 MB
32 MB-Dual 32 MB-Dual 8 MB-Dual 8 MB-Dual
32 MB-Dual 32 MB-Dual 16 MB 16 MB 96 MB
32 MB-Dual 32 MB-Dual 32 MB-Dual 32 MB-Dual 128 MB
1. 8 MB = single-bank SIMM, 8 MB in size.
2. 8 MB-Dual = dual-bank SIMM, 8 MB in size.
3. 32 MB-Dual = dual-bank SIMM, 32 MB in size.
Table 4 64-Bit DRAM Configuration for Cisco 3640 Routers (continued)
Bank 0 (SIMM 0) Bank 1 (SIMM 1) Bank 2 (SIMM 2) Bank 3 (SIMM 3) Total Memory
Table 5 SDRAM Configurations for Cisco 3631 Routers
Bank 0 (DIMM 0) Bank 1 (DIMM 1) Total Memory
— 64 MB 64 MB
64 MB —
——