If you're talking the Pentium G860 Sandy Bridge 3.0GHz, it will work great. If there's any bottleneck at all, it will be minimal. You should be able to get good frame rates up to 1920x1080 with high-ish settings. Even better if you game at lower resolutions.
if you are saying that your CPU is not working properly that means first of all you should have the complete knowledge of CPU and its proper supply then only it can work