Depends upon the lengh of the film.
If its 90 minutes to an epic 3 hours there will be a difference.
Time it takes...Hours (cant be precise) It's best to shut everything down that runs in the background and leave it to run. If your using your computer at the sametime this will slow it down also. This may also make compression errors, which means when played back the film will stop and start and the sound will be all over the place.
THe spec of you PC is high so it shouldn't be any trouble for it - Just going to have to wait.