How to lower speed in nero?


i appologise in advance for what may prove to be a bloody stupid question;

first my specs;

windows xp pro
gigabyte ga-7n400-l motherboard
i gig ram
plextor px-716a (shows as udma4 in ide properties) firmware flashed from 1.04 to 1.08 sucessfully - original tla #0304
athlon 1700 cpu
nero ultra edition
plextools professional 2.23

i recently bought plextor the 716a and got some media to use with it.the memorex dvd-r 4x media i chose is apparently hated by this drive and none of them have ever passed data verification in nero.

all these were burnt at 4x because no other speed shows as available in nero at all - in plextools professional the drive claims to be able to burn dvd-r at 2x clv but in nero info tool the lowest setting is 4x.

is there any way of getting nero to let me burn these disks at a lower speed?

if theres any info i didnt realise was needed ill happily post it -i hate to waste these disks as i spent nearly all my money on the burner :o

the burner functions excellently with the other disks i bought (tdk 4x dvd+rw ) with scans showing pie below 20 all across the disk and no pof at all.but these arent really what i would like to use for every backup dvd i ever burn.
end edit

dr del