this is my second BenQ drive, here's a link to the problem with my last one.
i just got my BenQ1620 replacement this morning and installed.
1st thing i did was boot in to safe mode and upgraded my firmware to U9.
went back and burned 5 straight dvds and no problems. great 8X speed and check all the dvds and got very good burns
i left my computer running for about 10hrs came back and went to burn another dvd. well went to start the burn using dvd decrypter and 1st it took about 2 minutes for it to start which most the time it takes off in 20 sec.
i am using fujifilm 8x +r mij by the way
then the speeds wouldn't go any higher then 2.5x then about 20% through it gave me a i/o error and stopped.
i go to try another burn so i take the cover off my case and it starts at 40sec this time and stay's at about 3.6 to 4.0 x and finishes the dvd.
i had this problem with my last one also to where i would get a i/o error and very slow burn speeds. then i would shut down the computer start up later and it was back to normal
i have good air flow running through my computer and the temps last time i checked seem normal.