my experiences....

powermac g3, os9.2.2 with both ie 5.17 & ns 4.77

the version of netscape is ancient and it works extremely fast

ie on the other hand has the major slowdown problems (45 seconds to load on dsl where before it was not even 6 seconds) and it has been since whatever enhancements were made but i've been able to isolate a few things.

the advertising banners at the top of the page cause some of the loading problems (and the all pages "flash" as they load-part the page loads-flash to a blank screen, more of the page loads-flash to a blank screen, etc....

now, if i disable the following preferences (plug ins, scripting & activeX) there is some speed up but not as it was before the enhancements.

just my observations but i think it is an explorer issue which doesn't like the enhancements