In GPU intensive games, you won't have much of a bottleneck (at worst maybe a 10% loss which is roughly 6 fps if you are aiming for 60hz), but your CPU will hold you back in CPU intensive games. Have you thought about OCing at all and if you have what clocks are you at?
I should mention that since it's not released we have no way to know, but judging by dual GPU's like the 590 and the 6990 not bottlenecking on a pcie 2.0 @ 16x i doubt it will unless it has more than double the 7970 performance (not happening)
This doesn't apply to the cpu of course, which is why I asked about your CPU clocks. If you are OC'd you probably have nothing to worry about but you may be interested in a mobo/ram/cpu upgrade later this year or next year as new games come out.
Interesting question. I had a 9450 which is stock 2.66 and easily overclocked to 3.2. I'm sure you should be able to get the 9550 to 3.4 and that should suffice for now. I wasn't getting any lag in games but now with BF3 and newer multiplayer titles I'm not so sure that CPU could hold up.