If 3-D max is your thing, u shud have gone with an i-7 atleast. the HT enabled processors would have been the best bet.
processing power is paramount in rendering. unfortunately u probably cannot even overclock your processor, since i don't think itz an option on your motherboard.
the best thing wud b to ditch your system (except for the quadro fx1800, ofcourse), n build an i7 based.