I'm creating a 360 degree panoramic effect. However the image is moving rather jerkily

does anyone have any solutions for making the movement more smooth?
Apart from upping the frame rate that is.

here's some example code:

Code:
if (_xmouse>300) {
 moveDegree = 25-((Stage.width-_xmouse)/10);
  combined._x += moveDegree;
}
combined being the image(as a movieclip)

any suggestions greatfully appreciated

cheers!