to answer in short, yes, but by how much will depend on the program you are running, weather the program is more CPU or GPU intensive. If you have a CPU that clocks in at a maximum 3.5 GHZ turbo speed stock and you play a game that makes the CPU run at about 90% of the clock speed, with the GPU running at about 60-70% and then you overclocked too 4.5 GHZ, which then alleviated a bottleneck by increasing the amount of instructions per clock cycle, therefore making the program run faster and smoother and send more render frame instructions to the GPU which will increase the GPU usage and the fps. However, the CPU isn't always the cause of bottlenecks. Sometimes a GPU can just be flat out weak to begin with. Say if you pair a core i7 with a GTX 660, the core i7 will usually have a very low usage percentage due to the fact that the CPU is just sitting idle half the time while the GPU is trying to render the frames that are sent to it by the CPU, and the low amount of vram doesn't help either. For a bottleneck like that, overclocking the GPU would help more but honestly, if that was me, I would just upgrade the GPU.