There are many graphics cards of the 5800 series, would you please state which one.
All three of them will run it, to different levels of proficiency, from the basic HD 5830 to the middle of its class HD 5850, and then to the top of class HD 5870 (the X2 was a "59"-something, as I think I recall). We won't be able to say "how well" your PC will probably do until you are more specific.
witch one is better gt320 or 9800gt?
It ought to be the old 9800 GT. I don't think that the GPU Review has anything to do a side by side comparison for any "20s" other than the 220 and 520, but I'll look there anyway and re-edit if it's yes.
I was right, both times, no such "320 at GPU Review.
Here's the Gt 520 compared to a 9800 GT:
http://www.gpureview.com/show_cards.php?card1=650&card2=575