Where did you hear that?
Check out this thread on Lightscribe times between 1.0, 1.2 and 1.3 (unavailable) media.
These are the standard times with 1.0 media:
Setting Title only Title & content Full label
Best < 4 min. < 9 min. < 29 min.
Normal < 3 min. < 7 min. < 24 min.
Draft < 2 min. < 4 min. < 18 min.
So yeah, the LG will burn a Lightscribe disc in 5 minutes, if there's practically nothing on it. AFAIK, Lightscribe media is the same as any other, you can't write 4x discs at 16X (and before the nitpickers jump in, there's no OverSpeed patch for LightScribe).
Short course: Given the same media version, image and software, every burner will take the same amount of time to burn.