  It would be good to know how much total memory you are looking to have but 8x 8GB (total capacity of 64 GB) sounds economical.   16 GB memory modules do cost a little more but provide room for future memory upgrade. Yes, the R510 server has a rather unique memory population guidelines. For CPU A, it consists of 3 channels; CH0, CH1 and CH2. CH0 comprises slots A1 &A4 while channels CH1 and CH2 comprise slots A2 &A3 respectively. A similar pattern holds for CPU B. Refer to the diagram below: [IMAGE] In populating memory, the memory in each channel has to match and being populated in the strict order of A1 (for 1 DIMM), A2 ( when 2 DIMMs are used), A3 and lastly A4. Note that the memory DIMMs on CH0 do not necessarily have to be same, they can be of different capacity with larger size module populated on slot A1 and the other on slot  A4. See the Users' Guide for more information: [URL] 
Hi, I have a PowerEdge R510 with eight 4GB DIMMs. I want to add memory in the most cost effective way possible, but don't understand what I can replace where and have a balanced config. Can anyone help me sort this out?
Memory config for PE R510