A GTX 970 requires 145 watts, and it was just released not even a couple years ago. You mean to tell me that they found some way to put that kind of power in a cellphone now? Wow! What a world we live in.
Bring down the max opacity down to 0.7, or something. Right now it looks very strong. Also, the start distance is in Unreal units, so 1 unit is the equivalent of 1 centimeter. At that point, might as well set it to 0 and save the instructions. If you want to change the exponent with a power node to pull the fog closer to the camera, you can do that. In my testing, the power node gets converted to an exponent to save instructions, so the cost depends on the value. Just know that integers are cheaper, 2 is the cheapest, and raising to a decimal or floating point value is definitely going to be more expensive. I’d recommend against having perpetual fog everywhere, but if you really want to do that, you can plug in a value to the minimum on the clamp, giving even areas up in your face some amount of fog. Again, this is not a good idea. The purpose of the start distance was to push the fog away. If you want to have a lot of fog everywhere, I’d suggest lowering the depth (so the fog ramps up quickly) and lowering the max opacity (so you can still see what’s going on). The power node can also come in handy to push or pull the fog by depth. Just replace the multiply “exponent” node with a power and an input.