PowerEdge SC420

I purchased a Dell SC420 server several months back and I was given a memory upgrade that arrived after the server. The problem is that the server arrived it had 2 x 256 DIMMS and they shipped me 1 512 for my free Doule Your RAM upgrade. I immediately called Dell and told them that this was incorrect and I needed the chips in pairs. They insisted that it was OK to install the single 512 chip and that was that. Ever since I recieved the system it constantly gives me NMI Memory Errors when it get's put under any processing demand. I have called and argued with Dell endlessly and they insist that it isn't the RAM. I finally gave in and tried to purchase a second matching 512 chip but I can'd find anyone that still sells a DDR2 PC2 3200/400 ECC nonregistered DIMM. I think that I am going to have to purchase 2 new matching 512 DIMMS.

It also sounds like the fan always runs very unevenly as far as speed is concerned. It almost sounds like the server is constantly getting uneven line voltage. I know it's a variable speed fan, but this constantly modulates. I know the line voltage is clean, it's on a UPS that cleans the voltage.

Any Ideas?