Cisco Cisco UCS B440 M1 High-Performance Blade Server 정보 가이드

Contributed by Andreas Nikas, Cisco TAC Engineer.
Feb 07, 2013

How do I get DIMMs of different sizes (4G and 8G) to work in the same B250M2 server?
Related Information

This document is based on a common customer issue based on actual Cisco TAC Service Requests (SR).

This document's scenario starts with a B250M2 populated with 24 X 4G DIMMs running on ESXi.

Next, more memory needs to be added to the server. 24 X 8G DIMMs are ordered. The 8G DIMMs are then
inserted in the available slots.

Now when it boots the server will not have "checking memory". If DIMM locations are swapped the result is
the same. It only seems to work when all 4G or all 8G DIMMs are installed.

Here are the assumptions in this example:

There are two identical CPUs.

1. 

All DIMMs are the same speed.

2. 

All the DIMMs installed have been verified that they are supported for this server and release.

3. 

All DIMMs are DUAL Rank DIMMs.

4. 

Refer to Cisco Technical Tips Conventions for more information on document conventions.

A. First, you need to understand the CPU to DIMM channel relationship as illustrated here: