To get the "best" performance and visuals on PC, you should aim for the following setup:
After you install RPCS3 and dump your legitimate PS3 disc copy of God of War 3 , follow these settings for the best performance:
This is a frame-pacing issue. Disable VSync in RPCS3 and force it through your GPU driver. For NVIDIA users: Open the Control Panel > Manage 3D Settings > Add RPCS3 > Set "Max Frame Rate" to 120 and "Low Latency Mode" to Ultra.