sound distortion and slow burning speed HELP plz?

ive been burning dvds using shrink and its been great but recently i noticed it takeing longer to burn and copy and the ripping video use to show it smooth but like it was ff the movie well now its jumps instead of smoothly reading it and i went to see if its my drive played cd's and dvd movies using 5 diffren program evem window media player and it has sound distortion and i think this is causing my burns and rips to slow down does anyone know what this could be please help