What will 2.8Ghz-533mhz FSB cpu on a 400mhz FSB mobo yield?

[rustang351c]

http://support.dell.com/support/edocs/systems/dim4300/specs.htm#1101572

Hi,
I'm trying to make the above Dell run a little faster.
My friend has a 2.8Ghz-533mhz FSB, socket 478 chip
Will it run on my 400FSB motherboard, and if so at what speed? 2.1Ghz?
(It has a 1.6Ghz cpu presently)

 

[jsc]

(400/533)*2.8 GHz or, yep, a 2.1 GHz P4.