You have the i3-540. I show that is supports a maximum of 16GB of memory, and does not support RDIMMs. You will need to contact sales to see if they have 4GB UDIMMs for sale that are compatible with the server. I don't have any listed in the sales tools I have access to. Thanks
I have a PowerEdge R310 server with Core i3 CPU and 4GB or RAM (model number: M391B5773DH0-YH9). I bought 4x 4GB of the exact same specs memory and installe dthem on DIMS 1, 2, 3, 4, but the server didn't accept it. I also tried manual's memory configuration, which also didn't work. I read somewhere, don't remember where, that PowerEdge R310 with Core i3 CPU requires special memory and can only be upgraded to 8GB. Can anyone confirm this. I need to upgrade to 16GB. If that's not possible I can stick with 8GB, but I need to know which memory sticks to buy.  Any help and/or suggestions are greatly appreciated. 
PowerEdge R310 Core i3 Memory Upgrade