Decided to give the game a try today. I never played pre-patch so can't say if there's been an improvement or not.
My specs/config,
i5 4690k @ stock
16GB DDR3 RAM
GTX 970 OC'd to 1,500/3,750
Game installed to HDD
Resolution - 1920x1080
Settings - All Maxed/Enabled except for Interactive Smoke/Fog which is disabled.
I haven't used any ini tweaks or uncapped the framerate, I'm playing with the standard install and Nvidia recommended settings.
Now, no matter what I do, the MSI Afterburner/Rivatuner overlay just flatly refuses to work in Arkham Knight. Works in everything else, but simply will not work in Arkham Knight. Not sure if that's because of the hotkeys I have assigned to it (F6 to toggle, F7 to enable, F8 to disable), but it just will not show up, so I have to enable the Steam FPS counter and alt-tab out of the game to check my current clocks.
But anyway, I've had a brief play and the game has stuck more or less constantly to 30fps. The only dip I've noticed was when coming out of a cut scene for a split second where it dipped to about 26, then back to 30. Even when gliding or using the batmobile, I get a consistent 30fps.
I have noticed though, that when alt-tabbing out and checking Afterburner, my GPU RAM has downclocked to 3,000 and the core has downclocked to 1,100 (Though Arkham Knight isn't the only time the core downclocks a bit, in Kombustor it downclocks to about 1,365, but other games I get the 1,500)
Just wish I could get the RivaTuner stats working in the game so I could get some more details.