Sorry for the lack of info earlier...
1) yes, I meant to say OverSPEED and not Overburn.. sorry for the confusion
2) the Verbatim +R DL discs I have been using have the media ID: MKM 001 -- maybe this code isn't meant for 8x speeds; however, I do have a 20pk of Verbatim +R DL's that I haven't opened up yet that specifies on the label as burning up to 8x speeds -- sorry to say these say MKM 001 as well so ONLY 2.4x burn speeds
3) I've been using Nero CD-DVD Speed 4.50 & DVDInfoPro 4.36 to view each media's information and to test them as well
** I just don't understand why a DVD writer (DW1620) can burn these +R DL's at 4x and a more recent DVD writer (DW1655) can't even go over 2.4x!!!