Its more of a issue of how will Windows use the paging file. Even with ample RAM, Windows, especially XP still makes extensive use of the paging file. What I've done for years, even before XP, was set up a seperate partition and create the paging file (also called swap file, depending on the Windows version) there.

In older versions of Windows upon shutdown it would kill the swap file. To save a few seconds in booting which apparently a lot of people complained about they no longer wipe the paging file so it doesn't have to be created a new each time you boot. This causes two problems. The first is a security issue. File slack gets left in the paging file. If you use your computer for sensentive things you wouldn't want to fall into the wrong hands, such info could easily be recovered by any decent forensic application. The second problem is over time the paging file can get badly fragemented since it can't be touched while in use. Since its always in use when you run your typical defragger, the paging or swap file can get badly fragemented. Since its used constatly that's a drag on performance. By having it in a seperate partition, every so often you can kill the paging file (remove it) THEN do a defrag, which will clean out all the clusters used, then set up a new one.