Well, is your current drive a 7200, and is it >1TB? Also include the manufacturer. FRAPS does have to also create and store the video. Though, your drive should not pose any problems there...I always leave the door open to possibility. At what resolution are you recording? That also has a large bit to do with it.
Plus, on top of all that, are you running 64 bit?
EDIT: from my experience...FRAPS saves in .avi which (for the most part) is considerably large.