From my experience with a friends 1.3 GHz XP machine running Norton AV and 128 MB or RAM - when you start IE and then quit and then start it again it takes a very long time, something like 20 to 30 seconds before its up again. After adding a 128 MB it is down to the typical few seconds.
Really? Wow. I don't have that problem. I can close my browser and reopen it in just a few seconds.
I get more annoyed by how long my win98 machine sits during boot up doing nothing but the WIN98 splash screen. 30 seconds exactly. No hard drive light, no cd or floppy lights, nothing. My life ticking away.