An interim patch for Batman: Arkham Knight on PC has finally been released, allowing PC players to get their hands on the game without crippling framerates. User feedback suggests all is going well with the new patch, which fixes the following:
Reduced frame rate hitches
Optimizations for system memory and VRAM usage
Improved performance on all GPUs (requires the latest drivers)
More Comprehensive In-Game Settings
Fixed low resolution texture bugs
Fixed hitches when running on mechanical hard drives (HDD)
More optimization is planned for the future, which will add more support and optimize the game for Windows 10. You can read the full patch notes here.