Lite-on 1693S

I have just bought a Lite-on 1693S 16X DVD writer, and have also a Pioneer 108
The pioneer burns 8x DVDs at 12x, but the lite-on will only burn the identical discs at 4x, I have upgraded the firmware KS09, but no improvement. HELP.
What can I do to improve the performance of the Lite-on.
These speeds are the same whatever brand of DVDs I use. (Mainly Infiniti or Datawrite)

J D G.

What is their MID? Use CD Speed to find out (Click on disc info).

MID TTG02
Tested drives using Nero and blank Datawrite DVD
Pioneer test drive records ave speed of 9.98 (max 12.03) (This is also the burn ave)
Lite-on test drive records ave speed of 7.70 (When burning it is only 4x!)
both tests using same dvd blank Datawrite Titanium 8x (DVD-R)
As the pioneer is only suposed to write at 8x, and the Lite-on is supposed to write at 16x I do not understand the difference. I am quite happy with the Pioneer but not so with the Lite-on.