just noticed something weird on my 2.6-x RHAS 4. When you add a swap (file) to a running system, it leaves a large footprint the size of the new swapfile in memory (as cached). Is this normal? Once it is rebooted, everything shows up fine.
did you create and populate a new file for that? if you just create a big file, it will remain cached, even if you don't use it as a swap file.