I created & tested this on a single core AMD 3700. I have a ATIX1900... (so a slightly better Graphics card but a weaker processor).
Its an old PC and I get 30- Refresh rate FPS constantly which is very acceptable for me online in some very large missions. This is a very Old computer as is yours.
(so I created it on hardware that is 5+ years old...and it works fine for me and all of the beta testers, many of whom have much weaker PC's. )
You could not even consider running Rise of Flight or newer sims on your PC.
We made this for ourselves and the groups that we play with. That its become public was never really an intention.
When the moders and modpackers will give us an universal modpack ? For all of usWe all do this in our freetime for nothing. Nobody is forcing anybody to use anything....
This may help with the clouds :-
http://specialaircraftservice.com/main/index.php/topic,1679.0.html