I am having a Gaming desktop at my home with GTX 580. The desktop was set idle from long time, lets say about 4 months. Couple of days ago i started playing The Witcher Enhanced Edition. After playing for these 2 to 3 days i noticed that need my GPU usage is now reduced very much. It is just around 30% of the total GPU. i checked my settings, its all fine, running on the maximum settings than what is the cause of such a low GPU usage ? My FPS is about 50 to 55 on the vsync, still I can see the game is lagging and shuttering . I done few tweaking on the Nvidia Control Panel but that even do not fixed the issue , I have done everything that possible like uninstalling and reinstalling the driver but still the same problem. Is there any specific reasong for my problems ? Also let me know how can i fix all these things. Thanks.