Just curious, is this video common and what mostly everyone is experiencing while driving the Batmobile?
https://www.youtube.com/watch?v=86g8UtO87h0
Similar to what you're getting? Constant drops to 0-5 fps or is the video an extreme example?
What's really fascinating about this is that it actually reminds me of old school PC gaming. I remember playing Crusader No Remorse on a 486dx2/66 and getting stuttering like that when things would explore. It was very common for lots of HDD access interrupting games back in the day. Heck, I remember in Deus Ex, when things would explode, I'd often miss half the explosion due to this. I use to think "man, those explosions must be AMAZING if it's causing performance to dip like this". Ahhh, memories.
Truth be told, the performance in this game is actually right in line with how Half-Life 2 ran at launch. Loads of stuttering that could become just as severe, very long loading times, and unstable frame-rates. This was on, for the time, solid hardware (Pentium 4 3.6GHz + 6800GT).
It's perfect now but, at launch, it was just as bad as Arkham Knight in that regard. It was just as unacceptable to me then as it is now, though, but others seemed less bothered by it. Of course, things WERE a bit different back then indeed. We expect better these days. Just had to chuckle to myself when thinking back to those days.
In 2015, Arkham Knight PC is 100% unacceptable.