because at times its just not worth the bother and that is apparant from the awnsers you are getting in thsi thread

its not worth the bother to put a good video card in a 6400 because the machien just cant pull it its not 9500 its not a 9600 it doesn thave 12 ram banks not dual cpu's

its old tired and the one new component wont suddenly breath new life in to an old computer it will just be dragged down by the minimum amount of ram the slow bus speed the clock speed etc etc

because that is exactly what you seem to expect

it doesnt matter what videcard you put in there it wont be turned in to amonster just because of anew video card

put a G3 in that thing then the video card will make a difference

cpu upgrades on the mac are ridicilously expensive and uneconomic these days and as far as that dell of yours goes depending on its age its either not worth it or you can only go so far depending on the bus speed and slot or socket form factor