I have a Maximus IX Code MB with 2x 8Gb Corsair vengeance lpx 3000MHz's. After I initially put it together I had no problems. After about a month, during boot I got a error code 3F(no memory installed). After messing about with it for a while I was able to get it to boot with RAM in slots B1 and B2 (the third and fourth slot). Now I do not know if my RAM is being slowed down because of it and or how to fix this problem. I have tried updating my bios and a CMOS reset as well as using a friend's ram(2400 MHz) in the correct slots (which I still got the 3F error code) - none of which helped me. Any suggestions on how to fix this would be appreciated.