I can burn full 4gig DVDs no problem and they work fine, it's authoring that's the problem.
I use WINAVI to convert to VOB, TMPGEnc to author and Nero to burn. It burns fine and does actually play, it's just that it stutters all the way through, it doesn't play smoothly like it should.
I've also tried burning with TMPGEnc and get the same results.
My burner is an LG GSA-4167BRL 16X Dual Layer Dual Format DVD ± RW and the disks I'm using are maxell DVD+RW's.