I love my 470, but damn, those 570's are making me drool!
I like to have a big fast card, but more importantly to me, is that I can play my favorite games with everything turned up all the way, at 1920x1080, and with never going below 50fps. For me, that means I needed to have a 470 to accomplish that on BFBC2.
I've got the same CPU as you and it's running at 3.5ghz.
Here's a question for the op: do you think I'd see any noticeable benefit jumping from 3.5 to 3.8?
Well maybe you need to widen your options while not being let down by the morons who post here that got their heads up their rears. You could go for one of the new Fermi cards but the benefits aren't going to be so great sadly however you could look into going with sli as a option but only if the cost is low compared to a new card. Second it depends on the games you are playing. Since you made a comment about a physx title you have yet another option but once again benefits are small if you were to purchase a lower end card for that purpose as a physx card.
Beyond that maybe you should look into improving your system else ware. In the end you have a rather nice system even now but don't let the rich millionaire brats with their 4+ghz i7s get you down.