Question on Plextor 12/10/32A Burner

I have a Plextor 12/10/32A and it has Plextor manager 2000. I use the Disc dupe to copy Cd’s. When I’m copying the Cd w/music I have no problems, but after I burn it to the hard drive, then put in a blank Cd, it starts ok, but the drive buffer jumps around from 30 to 100% throughout burning process. I check the newly burned CD and it seems ok. But the buffer did not use to jump around. Also, Adaptec 4 comes bundled with the pleztor 2000 software.
Any ideas here?

I thought about getting Nero 6, but wasnt sure it would work with burner.

Thanks, Danny