Speeding up flash

i keep reading that the new versions of flash run/parse code faster than previous versions, but i’ve always been confused as to what exactly that means. does it mean:

a: the new version of the flash player plays movies faster, no matter what version the swf was published in

or

b: when you export in a newer version, the process of the way its exported makes the movie go faster

or

c: something else?

…in other words, if i build a huge file in flash 5, then pop it into flash 7 at the last minute and publish it, will that make it run faster?

thanks
jason