Problem with DVD-RAM

[pedram19518]

I'VE m60 toshiba with UJ840-S DVD-RAM

but i felt it's slower than other cd roms and even it's very much slower than it's spec(# Read: CD-ROM (24x), CD-R (24x), CD-RW (10x), DVD-ROM (8x), DVD-R (8x), DVD-RW (4x), DVD+R (8x), DVD+RW (4x), DVD-RAM (3x), DVD+R(DL) (2.4x)

# Write: CD-R (24x). CD-RW (10x), DVD-R (8x), DVD-RW (4x), DVD+R (8x), DVD+RW (4x), DVD-RAM (3x), DVD+R(DL) (2.4x))

and when i benchmark it i find that it can't read more than 12x!!

when i compare it with UJ840-D DVD RAM with same spec i find that it can write and read with more speed than mine(with same er of nero and same kind of cd and....)

Please help me?

is it related to firmware or....

becuase i when i check internet i see many persons with this dvd-ram have this problem!!