I believe this is how it works, but correct me if I'm wrong:
If the res is lower, you get a CPU bottleneck because the GPU renders the scene so fast that the CPU can't keep up calculating the info that the graphics card needs. At higher resolutions, the GPU takes so long to render that the CPU is long finished with the data for the next scene.
At that resolution, though, you shouldn't be worried because even if there is a CPU bottleneck it won't be much and you should be getting easily enough frames even with the bottleneck, unless you plan to play Metro DX11 with 8xAA, which even that card couldn't handle at that res probably. What games?
You should be fine even if you do get a restriction i would think you will be too busy enjoying your nice new Graphics card to notice.
Basically the 460 would run faster with an i5 CPU but then if you had an i5 already then it would run faster with a faster i7 CPU.
The problem comes when you pair a really fast GPU with something like an old single core chip p4 etc. Bottlenecking as far as im concerned is where the PC is physically/noticably impared in its performance due to one componrent or more not being capable of keeping up with the rest of the system. Im talking games running like a slide show here.
You will get restricted in terms of Max FPS but i doubt very much that you will get any serious issues. The performance differance should be night and day compared to the 9500.