Will a 800 MHz FSB CPU work on a 400 MHz FSB motherboard?

Hi,

I have a Dell Dimension 2400 and want to upgrade the CPU from the current 2.4GHz Celeron 400 MHz chip (128Mb cache).

I was told that a P4 2.8GHz would work in my machine, so I ve bought a 2.8GHz P4 800 MHz chip (512Mb cache) … I just wanted to check that it’s safe to install an 800 MHz FSB chip on a 400 MHz FSB motherboard, before I go ahead and break something!

Cheers,
Darren