want to upgrade my cpu

Hi all, I have a Intel Pentium 4 (Northwood ) SL5zz (enhanced speedstep) Mobile -1.7 cpu in my laptop (toshiba satellite) it has a 852gm chipset. I want to know how far up the ladder I can take this with a faster cpu.

Everything being the same on the stats, I can go to a 2.4 cpu. except for the bus/core ratio which goes from 17 to 24.

If I bump up to a 2.6 then I lose the enhanced speedstep (which I don't care about anyhow and the CPUID string goes to 35W instead of the 30W/28.8W that the 1.7 cpu states.

Above that and the Bus speed goes from 400Mhz to 533Mhz. I suppose I can't push into that realm, can I?

The page of cpu comparisons is located below. If someone can say, "this is where the buck stops for you" i would appreciate it, because I don't know!

http://processorfinder.intel.com/List.aspx?ProcFam=826

 

to be a little clearer, I want to know if I must stay in the 400 MHz limit, or it any other issues are important.