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.