Your CPU has 2 cores/2 threads. In many newer games that will hold back performance. Going to that i5, CPU performance will no longer hold you back in a lot of games. At that point, the 460 will hold back performance, at 1080p or higher, in many newer games.
It's all about balance. Any time you pair a component of mainstream performance level with an entry level component, you are going to have a bottleneck. All of this depends on the games you play. Not all PC games have the same requirements.