Memory Speed

I have an Asus PC800 Deluxe board with 1gig of Corsair XMS 3200 mem. I can get 240fsb & stable sys. with mem speed set to auto. If I set it to 400 mhz sys will not boot. What speed is the mem running at on auto if fsb is 240. Is it 480? Is there any software that will show mem speed on an Intel 875 chip.

yes it is 480. when you set it to 400 its too slow, thats why it doesnt boot, just leave it on auto.