Regarding DVD-RAM

Can someone please tell me if it’s normal for the burn mark of the recording side of a DVD-RAM to still be visible even after performing a full format?

I would also like to know if it’s normal for a DVD-RAM to take about 18 to 21 minutes to do a full format?

I think it’s normal for a “burn mark” to stay visible until you write more data than the previous burn onto the disc.

DVD-RAM is slow, I’ve done a full-format and it took me 1.5hrs to complete. That was using a 3x DVD-RAM.

Burn mark will not go away after a format.
Format or writing to DVD-RAM is very slow.
Most burning apps when using DVD-RAM also verify the data during the writing progress so 12x DVD-RAM is slower than burning DVD-R at 12x