What is the fastest processor upgrade on a t40?

It is type 2376 and has 1.3ghz banias. Can i upgrade it to pentium m 755 2ghz ? What is the fastest processor i can put in there. I see that the m processor ending with 0, example 740, 750, 760 are 533mhz fsb and the ones ending in 5, ex 745, 755 are 400mhz. WIll the ones with 533 mhz work or do i need to stick with the 400mhz? i ask because the 533mhz ones are cheaper. Thanks