DIMM Error on Cisco 3925

[johnlloyd_13]

hi all,

i removed 2x 512mb on the 2x DIMM slots and installed a 2gb DRAM on a new 3925 router.

i get the error below upon bootup. tried to search on the web but doesn't seem to give me much info.

could the memory stick be unsupported?

System Bootstrap, Version 15.0(1r)M16, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 2012 by cisco Systems, Inc.

%SPD info: DIMM 1: Invalid SPD
%SPD info: DIMM 1: No DIMM installed?

%Dump of SPD info for DIMM 0:
00: 80 08 08 0E 0A 01 48 00 05 30 45 06 82 08 08 00
10: 0C 08 30 01 01 05 03 3D 50 00 00 3C 1E 3C 2D 01
20: 20 27 10 17 3C 1E 1E 00 06 3C 7F 80 18 22 0F 00
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 12 24
40: 7F 94 00 00 00 00 00 00 01 41 47 35 37 32 35 36
50: 38 46 47 38 50 36 49 4C 53 46 30 00 00 13 43 06
60: 17 75 DF 53 4D 41 52 54 4D 6F 64 75 6C 61 72 54
70: 65 63 68 6E 6F 6C 6F 67 69 65 73 20 20 20 00 00

%Dump of SPD info for DIMM 1:
00: FF 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

%SPD info: Mismatch(es) between DIMMs
           Installed DIMMs must be identical
ERROR: No memory detected! Stop.

[Ryan Young · Accepted solution]

Mismatch(es) between DIMMs
           Installed DIMMs must be identical

tells me that the two memory slots have to be identical to work.

[johnlloyd_13]

thanks! found it on a link:

http://www.cisco.com/c/en/us/products/collateral/routers/1900-series-integrated-services-routers-isr/qa_c67_553891.html

The Cisco 3900 Series uses symmetrical DIMM modules for increased performance, meaning that two identical DIMM modules must be installed into both DIMM slots at all times. By default, the Cisco 3925, 3925E, 3945, and 3945E ship with 1 GB of system DRAM consisting of two 512-MB DIMM modules. For the Cisco 2951, the default DRAM is 512 MB installed in a single DIMM slot. Any additional memory upgrades on the Cisco 2951 can be inserted into the second DIMM slot that is open and available.

[-SFL-]

Had this issue when taking out service module, have a look at the 2 DIMM located on the rear right of module and make sure they are both seated correctly. One must have popped out when reinstalling for me.