Smooth video capture

When I run a PowerPoint presentation by itself, the animations are very fluid and smooth. When I use the Camtasia plugin to record the same PowerPoint presentation, the animations become less smooth. Path animations are "jittery", and other things happen in fits and spurts. I have tried shutting down everything and running just PowerPoint and Camtasia, but it does not help. It's important that I get smooth output for my clients. Do I need to upgrade my hardware? My current computer has 16GB of RAM and an i7 processor, so it is not a piece of junk. But, I'm thinking it may not be good enough for what I am trying to do. Thanks in advance for the help.