Let's have a look at those problems:
Assassin's Creed IV Black Flag Fix
Fixing: lagging, low fps, shuttering, flickering, black screens, tearing, freezing and such issues
My spec is:
- CPU: AMD phenom II x4 955 be (x18 clock)
- RAM: 8 gb
- GPU: ATI HD 6800 series 1gb
- What drivers you have to use? Well for now there is a beta driver: Catalyst 13.11 b with the latest updates, it's stable
- Use this filter to download the right one for your graphics.
- Use this tool: Radeon Profile Tool, or RadeonPro for short, is a free, user friendly utility designed to unleash the power of AMD™ Radeon™ video graphics cards.
- Look at this config:
Uninstall this internal windows update.
This should work for you if not use this fix: