grainy smoke

ok so im messing around with some smoke and fire sims but my smoke looks really grainy :

http://imageshack.us/photo/my-images/823/unled2puk.jpg/
http://imageshack.us/photo/my-images/535/unledzl.jpg/

and looks nothing like the realism in the tutorial even though i followed the tut to the letter.

any idea why its so grainy? and how to get it looking more realistic ( im guessing high rez smoke divisions and the general smoke domain divisions, but my pc aint powerfull enough for the high setting )

also see how the flame ( if you can call them flames ) are going up with the smoke, any way to keep the fire near the bottom.

thanks:D

Can we have a screenshot for your material settings?
That’d be my guess as to why it looks the way it does. Andrew Price has a great fire tutorial in a .pdf format that goes over realistic fire material settings, if you want to take a look at that.

You need to decrease the step size in the material of the domain object.