You'll have better luck if you ask this in the graphics cards forum, but my opinion is that isn't a worthwhile upgrade. You're better off spending a little more for a GTX 460. Even a 5770 would be better than the 450. Stick with the 4770 and save your money if the 450 is all you can afford.
thanks for the advice.i think i will go for the gigabyte 5770 1 gig card...thanks again