It could be in some games like GTAV, Tomb raider and in total war series from CPU but same cand be said on the GPU. But rx 460 is good pick for g4400 in my opinion. Whats your ram? If u get i5 7500 u can buy a better card like rx570/80 gtx 1060/50 ti.
My cpu (Intel Pentium G4400) bottleneck my gpu (RX 460) or vice versa? I am soon getting a i5 7500 and am not sure if I should get a GPU instead.
Enable FPS monitoring or get Fraps. Make sure your frame rate is unlocked/VSync disabled.
Lower resolution and graphics. if your FPS increases = GPU bottleneck. If not, CPU bottleneck.
You could also use Task Manager to find out CPU usage. Above 90% would be a bottleneck.
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.