Hey guys,

I have a Precision 690 (A08 bios, 2x dual core 2.3ghz Xeons) with the memory risers and 1KW PSU that was originally working with 4x2GB 2Rx4 PC5300F RAM for a total of 8GB. I have 8 sticks of Samsung 2GB 2Rx8 PC5300F RAM for a total of 16GB that I'm trying to put into this system but I can't get it to recognize more than 8GB.

When I put all 8 Samsung sticks into the slots on the motherboard, this exceeds the 8 rank capacity and I get 8GB of total RAM, which is understandable.

With the memory risers, it doesn't matter if I put 4 sticks in riser 4 and 4 in riser 1, or if I put all 8 sticks into risers 1 and 2, I still only get 8GB. The BIOS reports all sticks as being present but the "installed memory" still shows up as 8GB. I can put every stick of RAM I have in there, which should be 24GB, but I still only get 8. 

All 8 sticks of the RAM I'm trying to put into the system are identical, same brand, same model. They were working fine in an IBM server before this which seems to take the same RAM.

Is the RAM faulty, incompatible or is there something wrong with the computer?

Thanks a lot!