speed 4x and 2.1X on dvd +/- rw-tools

[passimal <passimal@gmail.com>]

Hello,

i use the DVD+RW tools on liteon 1633 SOWH 
but I ve some problems
my OS linux RH8 and ( or RH9)
in my boot conf I use hdc=ide-scsi when my dvd recorder is on master on ide2
when I have 2 ide ..
I can write on my DVD +RW  at 4X !!! very simply

On other Server
I ve only One ide port so i plugged myd dvd recorder in master ide1
and I change my boot conf hda=ide-scsi

I cannot write at 4X  only working at 2.1X !!
my conf :

linux RH8 or RH9
Disk SCSI Hot plug
Liteon 1633 SOWH (DVD writer +/-  ...)
Can you help me please

Stephane