Resolution: leave it as default.
Environment quality: high.
Texture quality: high.
Anti-aliasing quality: off. This option will kill your PC if you set it to maximum. With “off”, it looks more natural than with the next option, “FXAA”. I would recommend using “off”. This graphic option is the biggest resource demanders.
Shadow quality: leave it to “off” or “normal”. “Soft” shadow quality is consuming more resources than the non “soft” ones.
Reflection quality: high, it won’t make much difference. It looks better on “high”.
Motion blur: “off”. It’s more like a matter of taste.
Advanced
Ambient Occlusion: set it to off. This graphic option is the biggest resource demanders, after anti-aliasing. Even at “SSAO”, you still get low framerate on an older PC.
God rays: low.
Volumetric fog: on.
Vsync: off. I’ve noticed that the game moves much faster with vsync turned to “off”.
Assassin’s Creed IV Black Flag works great with these settings on my sistem, Intel I3 3GHz, 8 gigabytes RAM, ATI Radeon HD 5670 (1 GB RAM).
If you have lower hardware specs, set environment quality and texture quality to low.
How is the game working out for you?