Curiously, the asymmetry is normal in both cases, although there are deviations in the graph due to the correction of the laser power during the burn session. The jitter rate is, however, much better at 6x speed. It is also remarkable that besides fewer read errors the jitter rate varies less on the second layer of the disc. Let’s examine the latter effect closely.

Here’s another confirmation to what we’ve seen above: the jitter rate is good at 4x speed, but is simply excellent at 6x speed! I can’t find an explanation – maybe the manufacturer has paid much more attention to the 6x burn strategy. What about the second layer?

The jitter rate is somewhat worse, because it’s more difficult for the drive to process the second layer of a dual-layer disc, but the general picture is the same: the results are better with the disc burned at 6x. And another curious thing is that there are more errors but the jitter rate is smaller on the first layer. This may be explained by the better quality of the second layer of the disc (it is the second layer to be burned, but the first to be laid on the wafer).

Overall, the Plextor PX-716A boasts an excellent performance with DVD+R discs at any speed. It is only with the dual-layer media that it is not perfect. But frankly speaking, none of the available optical drives can boast an ideal burning of such discs, so we shouldn’t be too critical about the new Plextor in this respect. The noticed defects will be most probably corrected soon – the manufacturer is updating the firmware at a very rapid pace.