I found out why this happened.   One of the memory modules I installed was a 4GB 4Rx8 module rather then an 8GB 2Rx8 module like the rest.   My bad, I should’ve checked before installing them 
Hi everyone, I am trying to upgrade my server memory, but I am getting the following error:   [IMAGE]   My initial set up was: 48GB (8GBx6) Slots used are A1, A2, A3 and B1, B2, B3   The upgraded set up that is giving the below error: 144GB (8GBx18) Slots used are A1, A2, A…9 and B1, B2, B3, B…9 (all of them)   Channels seam to match as all the RAM modules are of 8GB each. I am not sure what I am doing wrong.  Thanks in advance.
DELL PowerEdge R710 memory upgrade error