When ever I try to burn a dvd+r dl disc I get 4x write speed. This causes problem for me some times so I need to burn the disc at 2.4x, but when I chose 2.4x it says the following in imgburn:
So it automaticly burns it in 4x anyway.
I always use quality discs, only verbatim dvd+r dl and my burner is a samsung SH-182D. If I understood correct the burner too supports that speed, but it still wont burn it in 2.4x for me, clonecd does the same thing when I pick 2.4, burns it in 4x anyway.