We have a Supermicro X7DWN+ motherboard with two Xeon L5420 CPU's installed. There is a total of 14GB memory installed, however the BIOS is only seeing 10GB.
The memory has been tested in another X7DWN+ and all 14GB is visible. The CPU's have been swapped with another server, they both work. The board is brand new, we had an old one that has exactly the same problem.
The power distribution board has been swapped.
I am really at a loss as to what the problem is here. The BIOS version is the same as other X7DWN+'s we have.
There is a mixture of 2GB and 1GB dimms installed. If I remove all the 2GB dimms and just leave the 1GB's, I only get 50% of the installed memory detected by the BIOS.
Suggestions as to what to try next welcome!?