I'm using a Benq 1640 with BSLM firmware, solidburn enabled, overspeed enabled.
With TY t002 (8x dvd+r) I can use 12x and 16x and both burn incrementally faster than 8x.
But with Verbatim mcc003 (dvd+r 8x), when set to 12x they burn between 6-8x, never above 8x, and average is 7.3x. But if i set it to 16x it then burns between 6-12x at an average of 10x.
So the 12x setting basically just does the same thing as 8x and I have to set 16x to approximately get what 12x should do.