Newbie needing help with buying new RAM

[vamp]

Hi. I would like to add RAM to my computer, preferably a 512mb stick because I only have one slot left. Here is my setup:

Dell Dimension 4550
Windows XP Home
P4 2.4
256mb DDR 333MHz PC2700

I purchased this computer about 2 years ago, and I was wondering if I would be able to use pc-3200 ram in your opinion, and if I can, would I have to remove my current 2700 stick? I can always buy more pc-2700 ram to be safe. Is there a big difference in performance between 2700 and 3200? Thanks for any help you can provide

[Gecko]

[vamp]