I have an old server motherboard (ASUS K8N-DL) and I decided to upgrade the RAM by adding 4x4 Gbyte ECC Registered DDR400 RAM stick from Viking that are supported reading the board Manual, but after installed the system start to beep informing of a RAM error. If I mixed with DDR333 RAM the PC boot you see the whole RAM, but it is unstable. I was wondering if it is possible to add the support to this RAM by changing the BIOS or if it is sufficient to increase the RAM voltage.