I am also having the same problem. I use verbatim DVDs and I am only having this problem after I updated to the new 188.8.131.52 today. I dont remeber what the older one was but I think it was over 10 months old. I have always been able to burn at 2.4x with the same setup till today.
The supported write speeds show:4x,6x,8x,10x but the DVDs show 8x max.
When I first did the update I just installed new over the old and when it asked if I wanted to keep my settings I picked no. And after wasting my first disc I uninstalled and rebooted and tried 184.108.40.206 and 220.127.116.11 but keep getting supported write speeds show:4x,6x,8x,10x.
I was wondering if there is something in the settings that can fix this back to the way it was? or do you think I lost or damaged a driver?