Unfortunately I've found Fraps an enormous memory hog while it records. The lag is more to do with running two heavy programs at once than with something wrong with SE. The best thing you can do is either to use another recording program, or SE's built-in video capture.
But the built in video capture is too laggy and it creates alot of pictures
well , do you suggest me some good video recorder?
EDIT:Problem solved: Just the fraps key is same with the SE 's recording key
now its ok