Adjust the 2 distance ranges at the top. Fog nearest. Lower number is closer fog start.
Fog Distance will control the fogs far range distance.
Example: Set the fog nearest to 2 and the fog range to 8 and then adjust the fog intensity.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit