Pioneer DVD-RW DVR-108 16x burning

[snake2]

my Pioneer DVD-RW DVR-108 isnt burning at 16x when i select 16x it will burn at 6x untill 33% done then it slows down to about 2x then picks up to 8x then at about 50% it slows down to 0x then it picks up to 12x then at about 95% it slows to about 10x then picks up to about 13.5x then finishes the DVD. it does this with the ritek 16x discs and the tanyo yurdan 16x (TYG04) discs i have FW 1.18 hacked to burn at any speed.

i used DVD decrypter and watched the speed as the DVD burnt it was burning an iso of a movie

has anyone else had this problem and is there a way i can fix it i was thinking about just getting a new lite-on drive

anyone know if there is a way to make my 108 burn at 16x or should i just get the new drive?