I am playing with fire simulation and after various tests I discovered the fastest way and great result for fire, the secret is using the old default Workbench render.
My computer CPU have only 4 cores (Ryzen 3), and 16GB of RAM. My GPU (vega 8) is not recognized by Blender (I use Linux) then only the cpu do the job. 
I can render and make various adjusts to the fire in REALTIME and also render more than 2 frames per second in full HD resolution. 
As you can see in the pic I disabled all shaders.
I had some difficulty to change the color of fire, but changing the Color Management settings the result is very good.
And the Viewport Display menu can change the shape of fire like if a new simulation have preprocessed, but in realtime during the play animation. Then no delay to see the result. This is fantastic.
For simple fire I think this is the fastest way.
If somebody need help, feel free to ask.
I hope this tip help you.