Burner
 

So I have a Pioneer burner and it burns at 16x. I've never had problems before burning anything and suddenly about 25 DVD's into my 100-pack it will only burn at 1x, 2x and 4x. Anyone know what could possibly cause this? I'm not doing anything different, I didn't update any drivers, and I'm using DVD's from a 100-pack from which I've burnt 25 or so at 16x perfectly fine.