Even burning my most successful discs (TDK DVD-R 4x)
which I've had an almost 100% success with (too bad they're so expensive), about 1/2 of the time the burn speed ends up being only 2x instead of 4x. All the discs have come from the same batch, so it's weird that some are burnt 4x and others only at 2x.
This is using Nero 188.8.131.52 bundled with the burner
and v0049 of the firmware.
Is there going to be more updates to the firmware soon?