When does Fire/Smoke get realistic?

Hi!
Right now I am experimenting with fire after I did the same with water. Now from water I know that it gets really realistic with resolution 500 or higher, especially if glasses are involved.
Now I watched several tutorials about fire with setting up and manipulating the new material for fire / smoke. But I haven’ found a info about the realism of fire: When does it get really realistic? I tried to calculate Divisions 512 with High resolution / Subdivision of 2 but you know… calculated 6h for about 80 frames and I’d like to have about 150. Meanwhile the whole PC can’d be used :wink:
If you could share your expierience I’d be really thankful for the help.