Well, in FRAPS your monitor is your camera; your movie quality depends on your monitor. Get a look on the link below; it's a fake trailler. The image is smooth cuz it was recorded with a 120hz monitor and my computer is a sli system. If you wanna a good frap movie ask someone with a close hardware to do it 4 you.
http://www.youtube.com/watch?v=pkZAhYrLHi4
Obs: if you export the movie as a FLV file the image gets superb.