In Nero, there are typically up to three checkboxes in the drive options:
On the left, Underrun protection - you need a very good reason indeed to turn this off, though I belive you have to if you want to do a simulation (out it back on afterwards.
On the right (bottom) - DVD high compatibility - write at least 1Gb ... I believe that matters more in DVD-Video
On the right (TOP) - Smart-Burn or other auto-speed selection
Supposedly, this enables the speed to be matched to the media, but it's often too optimistic for any older or lower grade media, and can be pessimistic for other media.
At one time, "Smart-Burn" did refer to Liteon's answer to "Burn-proof" - and Burn-proof is to underrun protection, what "Hoover" is to vacuum cleaners - if tyou say it, people know what you mean, even if it's not the actual thing!