Serious Lag issues with Photo Booth and iChat

Ever since I installed Leopard on my mac book pro, I have had terrible lag problems with the movie option in Photo Booth (sometimes even freezing my computer) as well as the video chat in ichat. With Tiger, lag was never a problem when I was on ichat. I have the 1.83 GHz Intel core duo, so I'm surprised this is happening. Any ideas would be very helpful! Thanks!