Nero CD-DVD Speed and WinXP x64?

Recently I changed my system and I got an Athlon64, and with this I also moved to Windows XP x64 edition.

I found this problem with CD-DVD Speed:
it always scan everything on max speed, for example DVD Disc Quality tests, even if i set it to 8x, it starts at 6x and continues upto 16x.
While if I use the DVD Benchmark, it starts at 10x and goes up with a CAV (check attachments)…

I also downloaded the latest cd-DVD Speed version from the cdspeed website, same results…

anybody encountered this problem? any solutions?