I have a server that came with two sticks of 2GB PC2-6400 ECC ram (Hyundai). We also bought two sticks of Corsair CM2x2048-6400C5C (PC2-6400). So I installed all 4 sticks and the machine started beeping and wouldn't boot. So I took out the factory RAM and tried just the Corsair RAM and it booted fine. Took that out and tried the factory RAM and it booted fine.
So I was super confused and then read about mixing ECC sticks from this post. I then thought I'd consult the technical manual of the system board. The odd thing is that it states it requires
unbuffered RAM to work. There's no real indication to me that the modules can't be mixed.
Could someone try to explain what the problem could be?