Re: Pixelated Fog/Smoke/Fire

Perhaps setting your 3D settings to be Application-controlled will help?

You can get to this in the Nvidia Control Panel, from Manage 3D settings > Program Settings. 

One thing that does pop out is Anti-aliasing -  Transparency. I know mine on my modest work PC is set to off by default. Perhaps if yours is off too, enabling it will help?

I know this is guessing, but I hope it leads in the right direction, thanks.