Actually, you are not correct to assume that. I do own an Asus GTX460 1GB DirectCU, which is now in my Media Center. But that does not necessarily make me any more competent at evaluating the situation either.
Again, as I said in the beginning, it does matter depending on the specific games. That Tom's Hardware article you provided clearly stated that even tough a game is DX9 (Left 4 Dead) it can take advantage of 4 cores, while newer games will only benefit from 2, so the fact you have DX9, 10 and 11 is not an exact indication of performance. It should be done on a case by case analysis. But anyhow, it will make a difference, perhaps not noticeable in games that get to 60fps+, like you said.
The best comparison i could find is this one, between an Athlon X4 630 @2.8 Ghz, and A Phenom II X4 920 @ 2.8Ghz. They didn't test many games, but yes, you can see there is a difference, but admittedly not a major one. However, I'd like to see Far Cry 2 tested at the highest settings. It's already on the border of smooth playability as it is. I'd also like to see Crysis, which was only tested at medium settings with Enthusiast Physics - there are other parameters that also affect CPU performance which were left at Medium. Remains to be seen if it would behave the same in other games. In other things besides games tough, such as productivity, it will show a sizable difference.
Edit: According to that bench tool, even the lowly 2.3GHZ Athlon II 605e is pretty good in those games
Edited by damric - 5/7/11 at 6:07pm