are you sure they dont go into slots 1 and 2 or 3 and 4?
take a screenshot of cpuz, the "memory" tab and the "spd" tab and lemme see it.
take a dig. photo of your bios screen and post it so i can see that too if possible, i am not familiar with your mobo.
lol actually the "maximum" speed is waaaaaaaaaaaay more than 400mhz, amigo...post those screen shots. i have the same ram, along with some gskill, that i split time in the rig with.