I'm having exactly the same problem. I have a 48/24/48A and recently I upgraded to 1.04. I use Plextor and Tayio prof disks and both make an extremely loud noise when writing or reading with high speed. the sound coming out of the cd is similar to the noise an 747 makes during takeoff!
My drive is old, I bought it when it was first released, but thought it has this problem only with "unbalanced" bad branded cdrs. But hey, it makes noise now with Plextor cdr disks! This is unacceptable!
Anyone else solved this problem by downgrading to 1.03 again? Thanks!