What ram are you using?
1:1 means youd be running the RAM @ 533MHz
your bus speed is 400mhz i assume as it says in your sig? that means that if your ratio is set 1:1 your ram speed will be 400mhz, so you need to up the bus speed to 533mhz? although the chip probably won't do that so to run your ram at full speed u need to run a 1:1.33 ram ratio?