1653S CS0T trouble

My drive was initially a single layer drive before I upgraded to the double layer CS0M. I think it may have originally been a 1633, now its recognized by the computer as a 1653.

After the upgrade I could finally write to disk fairly quickly and I could get reliable writes, before I was seeing files that weren’t written, etc.

More recently I had noticed that the speed had taken a big hit, namely it was taking around 1.5-2 hours to write a software DVD, no video.

Last night I decided to upgrade the firmware to CS0T. It sped things back up to around 30 minutes for a complete 4.2-4.3Gb write. Not bad. The problem has been that the write isn’t complete. I always double check the write by copying the DVD back to the hard drive. I can’t do this with any of the DVD’s that I’ve made. The files won’t copy back over. I am doing Divx video files and only a couple of them on each disc will even play, most just cause WMP to freeze up.

I went one step further and tried to drop back down to CS0M. This caused the light on the DVD player to blink continuously from the time I turned the computer on until I turned it off. I did manage to successfully get CS0T reinstall, at least it seems that way. I also reinstalled my Nero software that I use to write the DVDs as well. Still I have the same problem, the disk that is made doesn’t work.

What should I try next?
Thanks

Even 30 mn is way too much!!!
Is your DMA activated?