Thanks again for responses. I have already changed thermal paste. Before changing thermal paste, temperatures were from 70 to 95°C, but now when I changed it, temperatures, like I said, are from 70 to 80 °C. So, changing thermal paste helped me partly. I am considering to buy a CPU and case coolers, but firstly I want to know where the problem is exactly. Also, I tried the method, which essenbe offered me. I used that program (GPUz) to check my GPU stats and information when playing. All I can say that there, in the GPU stats log, is almost no difference when the game runs smoothly or laggy and with low FPS. GPU fan speed is from 40 to 45% and the temperature is from 40 to 60°C. But when I am playing a game, GPU load is from 90 to 99%. Does this mean something and can affect my games FPS? Like I said in my first post, I think that there can be RAM issue? Maybe bad sectors causing the FPS drops in my games? I think that I need to check my RAMs with program called Memtest86+. Can this program help to me? Anyway, that was my reflections about the problem. It would be great if you, guys, or other could give me more advices and help to resolve this annoying problem. I am looking forward to this thing! Waiting for more helpful advices!