judging from some other people's posts, i would say 4x is about average. the key is how well was the movie ripped, and if your media is good. Here's what I do: -I always try to buy the best dvd-r media (Verbatim, Taiyo Yuden, Ritek) -I rip the movie with dvd shrink and use adaptive error compensations and deep analysis. (don't compress too much, use dvd decrypter when needed) -If I downloaded the movie I use 4x, if it's a retail dvd I ripped I use 8x. -I have a Lite-On 1633-s (or something like that) I don't think it's great, but I don't think it's crappy either.
The movie is choppy at the end because it gets to the least reliable part of the disk. Set your target for 4300.
using good media (Taiyo Yuden and or Verbatim) amd a good machine ,burners,memory etc. you can burn at 8x as long as the media is rated 8x , most in here go 4x max. though ,using good blank media is the trick