help me fix my pc

Hey guys.. I have intel core 2 quad q8400 2.66ghz , 6gb ram, gt 710 2gb ddr3. I am facing sooo much lag spikes and freezing in my games....like in CS GO the people who have the exact specification like mee they get such a good fps ( in 1080 low setting 40-45, in 720p 70-80fps, in 1024*765 about...