We've got several Supermicro servers that we're trying to upgrade the RAM on so that we can run virtual servers on them, but only a few of them took the RAM upgrade that we performed. We double-checked to make sure that the RAM was all in the proper slots and that the RAM itself wasn't bad. We also flashed the bios to the most recent version to make sure that wasn't the problem, but to no avail. A large number of our servers just won't see more than 4GB of RAM. The ones that do don't have any apparent differences to the ones that don't, so we're completely stumped.
Any ideas or suggestions anyone can give will be extremely helpful.
Best Answer
Have you tried setting the BIOS 4GB PCI Hole Granularity to 1GB? Also make sure you are using pairs in channels 1A-2A, 1B-2B and so on.
When I say 1A-2A that means slots 1 and 4. This board has the slots going in order: 1A, 1B, 1C, 2A, 2B, 2C. If you use 2 sticks you can use either 1A-2A or 1A-1B configuration. When using 3 sticks: 1A, 1B, 1C. When 4 or 6 you must pair up the memory banks: 1A-2A, 1B-2B, 1C-2C