Think you need to sort out the pictures link!?

Sounds to me like the FRONT SIDE BUS TO NORTH BRIDGE RATIO option found in bioses which I think goes like this: (jump in and correct anyone?)

you set the cpu Mhz lets say 400

you choose a strap (if there is one) this will give you a choice of certain dividers such as 1:1 1:2 etc

you choose a ratio to suit your ram

on a maximus choosing the 333 strap gives me a choice of:

1/1 giving a ram setting of 400*2*1/1= 800

6/5 400*2*6/5= 960

8/5 400*2*8/5=1280

2/1 400*2*2/1=1600

changing straps gives different ratios of:

1/1 2/1 3/2 4/3 for the 400 strap

1/1 2/1 for the 200 strap

2/1 3/2 and 5/4 for the 266 strap

So to summarise: Strap or no strap find out the ratios available and calculate as above

selected cpu speed ,multiply by 2, multiply by divider of choice to get ram speed

incidently the straps produce fsb speed you talked about ie 333*4=1333