Yes, the processor has to match the original EXACTLY, and each processor must have identical memory configurations.
Hello .. I have Poweredge R410 Server with one Xeon CPU and the bios version is 1.9.0 .. some members mentioned here that one Slot can take up  16GB RAM from BIOS version 1.1.5 , if this right I need to know if I can do this with one CPU and what type of memory shall I use .. in brief I want to fill 4 DIMMS with 64GB of RAMS . so my questions is : 1- can I use 64GB of RAM with one CPU in just 4 DIMMS .. BTW my BIOS version is 1.9.0 ? 2- what type of RAMS shalld I use and what Model and ? please I need help as soon as possible because I will proceed with the purchase  tomorrow from a reseller in my country and if I got wrong Type of memory I won't be able to replace them !   Thanks in Advance  
Hello PowerEdge R410 Memory Upgrade