Hello Dookooo You can put 4x8GB DIMM's in A1-A4. Try it with just the 2x8GB DIMMs in slots A1 and A2. The server should default to optimizer mode and you should have 16GB of memory available. The memory may be getting disabled because you are mixing UDIMMs and RDIMMs, you have A1 and A4 populated instead of 1&2, or several other possibilities. If you still have issues with the DIMMs provide more information about the DIMMs you are using.   The L means low voltage. Thanks
Hello and Good Day ..  i am From Egypt and i just bought my R410 server .. well.. my server is equipped with 12 GB of Rams and i wanted to equip it with 32 GB of Rams .. so i decided that i will install first 16 GB 2× 8GB .. when i did this and started the system it shows that i only have 8 GB of ram .. i tried to check the memory setting for the bios and it's all disabled ... i can't change the mode of memory in the bios ... my server has one CPU .. i am newbie to this .. so please can anyone tell me how to upgrade to 32 GB of rams for one CPU and which mode i should select in memory settings and what type of memory should i buy and provide me with links to the recommended Rams .. PS: i noticed in a this forum a problem like this and the customer said that DELL support agent advised to install PC3L RAM and not PC3 ... i didn't get that .. so if anyone answer me and explain as soon as possible please  thanks in advance 
HELP .. PowerEdge R410 RAM UPGRADE