I just put in the drive with a fresh windows xp installation and then installed Nero 55917. The drive is flashed with 6S08 firmware.
Opening Nero Infotools told me my drive was 52x read, 52x write.
Starting Nero I noticed that 40x was my max speed.
Opened Infotools again and now it says 12x read, 40x write.
windows xp sp1
MSI kt3 ultra-aru
athlon xp 1700
plextor 8/20 (scsi adaptec 2940)