CPU Setup using the Bios SoftMenu

I bought an ABIT BD7-Raid motherboard which supports a Pentium 4, 1.7gig CPU at 400mgz bus speed. So I installed this CPU. Reading the manual, it says I must setup the CPU using the softmenu. It also says that I must enter the CPU operating speed as a function of External Clock Speed x Multiplier Factor.
I figure that Bus Speed and External Clock are the same, so I think that I should use a External Clock speed of 400 and a multiplier of 4.25. The manual suggests not using a clock speed of over 100. I'm confused. It sounds like the manual is insisting on me entering 100 x 17. Would not this defeat the benefit of utilizing the 400mgz speed of the CPU and Motherboard capability?
Please give me some good advise here so that I need to do this only once.

 

17 x 100 is the right number.

the 400 refers to the internal speed of the processor, not the system bus speed.