Help: About COMBO Driver

Hello,

My motherboard is GA-6VXE+, and I have a BENQ 5232X CD-RW driver and a
generic COMBO. As we know, the motherboard supports UDMA33/66. And the
COMBO is Master, the CD-RW is Slave. When I boot the computer, the screen
shows that my COMBO is 'UDMA 49', I don't know what happened on earth. I
can use these drivers well.

Please tell me the reason and more details.

Thanks very much.

Amy Lee