To get the best quality video - especially on slower machines - try the following:
Go to Settings, and make sure you are using the MPEG-2 video format. You can also try one of the Recommended Settings options for slower PC's.
Try recording from a smaller video window by resizing your player to 1/4 of your screen, or no more than 480x640 pixels. This won't affect the video quality (since video is scaled UP from smaller sizes to fit a full-screen picture). This will require less computer power to capture, which will make for smoother videos.
For Windows XP, click "Start", right-click "My Computer" then select "Properties". Click the "Advanced" tab. In the Performance section, click "Settings". Choose "Adjust for best performance".
For Windows 7 and 8, right click on “Computer” on your Desktop and select “Properties”. Choose “Advanced System Settings” on the left. In the System Properties “Advanced” tab, click “Settings” in the Performance section. Choose "Adjust for best performance".