Good morning, Mohasin. Make sure the bios is fully updated on the server as well with the original memory installed.  Then try 2 4gb DIMM's.  These should be compatible. Regards,
Hello All,I have Poweredge 1950 Server with 1x4 GB Onboard RAM. I ordered  Hynix 4GB 667 MHz FBDIMM RAM to upgrade the current server.After putting these new RAM unit , Poweredge is unable to boot and displays NO Memory Alert. All the previous banks of RAM were replaced with set of 8 new RAM to attain effective capacity of 32 GB. There was no mixing of old 1 GB and new 4 GB RAM units. Let me know if there are compatibility issues of the RAM, Hynix Part No. (HYMP151F72CP4N3-Y5-AC-C) and HP part no. (398708-061) with Dell poweredge 1950.  Regards -------- Mohasin
PowerEdge 1950 RAM upgradation issue