I have a TYAN S2875 dual opteron (275) motherboard and have recently purchased 4 x 2 Gb of DDR400 PC3200 ECC registered memory modules (8Gb in total). These are matched pairs, in dual channel configuration and are on the approved vendor list. I have tested each stick and each one works fine and shows its full capacity. However when all sticks are inserted, system properties only shows 3.43Gb!! (should be just less than 8). Even when 2 sticks are taken out leaving 4Gb left, the system properties still only show a maximum of 3.43Gb available!! Is there an option in the Bios that I need to activate or something else I'm not doing correctly? I'm running Windows XP Pro SP2 and mobo bios is all up to date. Any Ideas?