  2.) I tried looking all over the internet trying to figure out why channel 0 is better to put the larger? It seemed to make sense to me to put the 2 x 4GB into channel zero, as that would bring to total RAM to chan 0 = 8GB, and then if I put 8GB in the others slots, that would make all "Channels" equal in size, or am I missing something?   I mixed up the guidelines with another familiar server. Refer to the diagram below: [IMAGE] The memory configuration of the R410 server is rather different from the rest. Processor 1 has 2 memory banks consisting of slots A1, A2 & A3 and the other bank is just slot A4. On the other hand, Processor 2 also has 2 memory banks consisting of slots B1, B2 & B3 and the other bank is just slot B4. For optimal memory configuration, memory in each of the banks has to be the same. We do not mix the memory sizes on these banks. Accordingly, you would have as observed Slots A1, A2 &A3 and B1, B2 &B3 = 4 GB and A4 &B4 =8 GB. In this case not necessarily "Channels" equal in size but banks equal in size. You are not missing a thing here! For more information,see pages 119 - 123 of the Users' Guide: ftp.dell.com/.../poweredge-r410_owner's manual_en-us.pdf   3.) I figured out that if I put, 4GB modules into slots 1,2,3 and 8GB into slot 4, and then reverse for the other server. I do NOT get the "unoptimized configuration" messages on boot. That also means I have one server with 40GB of RAM and another with 56GB of RAM which is very nonoptimal for my needs.  What to do????   Unfortunately, you can't achieve 48 GB of optimal memory configuration with your current memory. For optimal 48 GB of memory you will need 6x 8 GB modules populated on slots A1, A2 &A3 and B1, B2 &B3 leaving slots A4 &B4 empty or unused.
I have two Dell R410 Servers 8 x 4GB sticks (2Rx4) 8 x 8GB sticks (2Rx4) I was hoping to put 2 sticks of 4GB and 2 sicks of 8GB per processor. for a total of 48GB per server. As it was my understanding that these servers have 3 channels. Ch 0 - 1&4 with 2 x 4GB sticks Ch 1 - 8GB stick Ch 2 - 8GB sitck  Should this work OK?  
R410 Memory Configuration question