First of all thanks to Nvidia for explaining how the game works and for explaining every thing how it works (even though i use Ati card) http://www.geforce.com/whats-new/guides/watch-dogs-grap....
So to finally start go to "Documents-->My Games-->Watch Dogs and there should be a file there called "GamerProfile" open it with Notepad under "<CustomQuality>" heading edit the following things. Now another thing you should remember is that you should always use "Custom" setting in the game and not Low, Medium, High setting because than the game would not use these settings.
1: Change "EnviromentQuality" to "low"
2: "PostFxQuality" to "low"
3: "TextureResolutionQuality" to "low"
4: "WaterQuality" to "low"
5: "ParaboloidReflectionQuality" to "low"
6: "VegetationQuality" to "low"
7: "TerrainQuality" to "low"
8: "GeometryQuality" to "low"
9: "ShadowQuality" to "low"
10: "ShadingQuality" to "low"
11: "ParticlesQuality" to "low"
12: "SuperSampling" to "0"
13: "RenderRain" to "0"
14: "SSAOQuality" to "off"
15: "DepthofFieldQuality" to "off

That's all you need to change and than save the file and than start the game and select Custom in settings in the game and i promise you will notice a drastic increase in the performance and loss in the Quality. And this tutorial is specially for the people with weak processors and ATI cards!!!
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