I would agree with Kenshin, this has been covered before in tonnes of posts. The 4120 is very picky on it's media, and prefers to have the best possible. Not much overspeeding on this drive, much to our chagrin. But the discs that do work, are usually burned very well. Best bet is to stick with TY media, or Richo, BenQ will work, but even the 8x that burn at 16x on the 6120, will only burn at 4x on this drive.