I agree there are a lot of variables. You should be able to burn fine at 4X
and no slower speed should ever be needed. I believe you get an advantages
with DVD+ format:
Why DVD+R(W) is superior to DVD-R
http://www.cdfreaks.com/article/113
Additional hints to help burning:
1) If your burning software has an Iso tab as Nero 6+ and above does use it.
2) Close the burning sessions.
3) Try the tip below:
Get to Device Manager by typing devmgmt.msc in run/win key + pause break or
Rt. click My Computer>Prop>hardware tab>Device Manager if you like 5 steps
instead of one cmd. If you're set to PMI here change to DMO and if set to
DMO change to PMI:
a.. Click the + in front of IDE ATA/ATAPI Controllers
a.. Double Click the Secondary IDE Controller
a.. Click Advanced Settings
a.. Under Device 1 Next to Transfer Mode choose DMA (or vise versa)
a.. Click OK
a.. Reboot your System
CH